Fix relay submitting extra parachain headers during reorg

[svyatonik]

closes #2838

So what happens here:

1. on-demand parachain relay starts and it finds RBH#17 ad R#32. Since there's no any RBH block at WBH, it decides to relay R#32 to WBH first;
2. at some point on-demand finality relay relays mandatory R#41 to WBH;
3. on-demand parachain finds that R#41 has RBH#26. So it decides to relay RBH#26 now;
4. it results in setting max_head_id to 26, meaning that the parachains relay now need to relay RBH blocks up to RBH#26 to WBH;
5. then reorg happens at WBH and now the best R block known to WBH is R#31 (another mandatory R block), which references the RBH#17. Since parachains relay goal is to sync up to the RBH#26, it decides to sync RBH#17;
6. this tx with RBH#17 gets mined;
7. then another tx with RBH#26 gets mined (because parachains relay keep doing what it needs to do).

What it means for us:

1. for Rococo <> Westend and Polkadot <> Kusama it is (almost) irrelevant, because if complex+batch relay is used, then it can happen only during initialization. So losses, even if they happen are minimal. But let's fix it anyway;
2. for complex+no-batch relay the issue is valid, because it may happen during regular operations, not only during initialization phase. We are using such relay in with-Bulletin chain bridge. But since bulletin chain is fee-free, it isn't a big issue there as well;
3. for standalone relayers this is also not an issue - they are designed to relay everything.

2024-02-15 14:30:10 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingRelayHeader(32) using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: None, para_header_at_source: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), para_header_at_relay_header_at_target: Some(HeaderId(2, 0x2b8cb1295cad9b2e1d70eae413eb98f78c399adc5b48931ae3d13feb6219c15c)), relay_header_at_source: 32, relay_header_at_target: Some(15) }
2024-02-15 14:30:10 +00 INFO bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Starting on-demand-parachains relay task
2024-02-15 14:30:22 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingRelayHeader(32) using old state RelayingRelayHeader(32) and data RelayData { required_para_header: 0, para_header_at_target: None, para_header_at_source: Some(HeaderId(19, 0x622b8a6ec5b57883270392c0ab7acdfdb1d8c291e45ab8d58e30eaeb3139701d)), para_header_at_relay_header_at_target: Some(HeaderId(8, 0x6d750ffacadf8c6264cd22b603fa8ed4372c26ace1304971b1550b4921091f32)), relay_header_at_source: 34, relay_header_at_target: Some(21) }
2024-02-15 14:30:34 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingRelayHeader(32) using old state RelayingRelayHeader(32) and data RelayData { required_para_header: 0, para_header_at_target: None, para_header_at_source: Some(HeaderId(21, 0x47603640d396d95fbc513f2c9f0cb214ea66ff248a6c10be7941862cedc9523a)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 36, relay_header_at_target: Some(31) }
2024-02-15 14:30:46 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingRelayHeader(32) using old state RelayingRelayHeader(32) and data RelayData { required_para_header: 0, para_header_at_target: None, para_header_at_source: Some(HeaderId(23, 0x3a48b31170c3cd1196d962cd21ace95ee567cea9498e47662803c7fe8e35943d)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 38, relay_header_at_target: Some(31) }
2024-02-15 14:30:58 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingRelayHeader(32) using old state RelayingRelayHeader(32) and data RelayData { required_para_header: 0, para_header_at_target: None, para_header_at_source: Some(HeaderId(25, 0xba4d61d36512fc4d45bccd327a0659f82e9c72ea90dc94ea057635908187f9b7)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 40, relay_header_at_target: Some(31) }
2024-02-15 14:31:10 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingRelayHeader(32) using old state RelayingRelayHeader(32) and data RelayData { required_para_header: 0, para_header_at_target: None, para_header_at_source: Some(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 42, relay_header_at_target: Some(31) }
2024-02-15 14:31:22 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingRelayHeader(32) using old state RelayingRelayHeader(32) and data RelayData { required_para_header: 0, para_header_at_target: None, para_header_at_source: Some(HeaderId(28, 0x698a69878e14ce704d4b0c57815c53629deec5b267ef8271fd6d393798f9b8b2)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 44, relay_header_at_target: Some(31) }
2024-02-15 14:31:34 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) using old state RelayingRelayHeader(32) and data RelayData { required_para_header: 0, para_header_at_target: None, para_header_at_source: Some(HeaderId(30, 0x1ca248c2bf3804e8a0ca35c528d8da1ba7353fc0734a619a2822085d6729ecbc)), para_header_at_relay_header_at_target: Some(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)), relay_header_at_source: 46, relay_header_at_target: Some(41) }
2024-02-15 14:31:46 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) using old state RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) and data RelayData { required_para_header: 0, para_header_at_target: Some(17), para_header_at_source: Some(HeaderId(32, 0xc3b1ac3e8899ac1a3107f3937cdd4ee6a6a9312f8f02104ccc1e365107cb60c4)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 48, relay_header_at_target: Some(31) }
2024-02-15 14:31:58 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) using old state RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) and data RelayData { required_para_header: 0, para_header_at_target: Some(17), para_header_at_source: Some(HeaderId(34, 0xffde679c3e3cc74770715c58a86fc180f163fff62ff431c2bc1e4357de568f35)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 50, relay_header_at_target: Some(31) }
2024-02-15 14:32:10 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) using old state RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) and data RelayData { required_para_header: 0, para_header_at_target: Some(17), para_header_at_source: Some(HeaderId(35, 0x78ddcd236a66972e4a7a80cd98e5d285b6fce7f37de1733ca6766b6e89acd3af)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 52, relay_header_at_target: Some(31) }
2024-02-15 14:32:22 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) using old state RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) and data RelayData { required_para_header: 0, para_header_at_target: Some(17), para_header_at_source: Some(HeaderId(37, 0xb4c113fb3eb02dae25aab2adb62fed7f6c2de42b91818d93e974edac734be30d)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 54, relay_header_at_target: Some(31) }
2024-02-15 14:32:34 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) using old state RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) and data RelayData { required_para_header: 0, para_header_at_target: Some(17), para_header_at_source: Some(HeaderId(39, 0x15a39d3d7b0ee050ff64892de1a801857de7be5542a04ff76aacdb472b81b4c3)), para_header_at_relay_header_at_target: Some(HeaderId(17, 0x4bb2fb3ea8cae387e571e3ea67691a9d0a8fffd5af8724b0ba749e989ac444ca)), relay_header_at_source: 56, relay_header_at_target: Some(31) }
2024-02-15 14:32:46 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state RelayingParaHeader(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)) and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(41, 0x5d11433d870b361eda09c5c95871b43dd48c7805def6d37ffead136774d14b09)), para_header_at_relay_header_at_target: Some(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)), relay_header_at_source: 58, relay_header_at_target: Some(41) }
2024-02-15 14:32:58 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(43, 0x09a2d3aee597dbf1b6d28f4f49c282653d262383c18cc69598f99f95d0295407)), para_header_at_relay_header_at_target: Some(HeaderId(26, 0xd625b47b4d472c5840e8656f50b676215b698aa2d7e9b830c0bfc17cfbdf650e)), relay_header_at_source: 60, relay_header_at_target: Some(41) }
2024-02-15 14:33:10 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(44, 0xecf8c174d0db20dbdd650760ca23b9c4ee486830108d3c900d8d63e11dfa6576)), para_header_at_relay_header_at_target: Some(HeaderId(35, 0x78ddcd236a66972e4a7a80cd98e5d285b6fce7f37de1733ca6766b6e89acd3af)), relay_header_at_source: 62, relay_header_at_target: Some(51) }
2024-02-15 14:33:22 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(46, 0xbad94c15b304ad249e6520dec948cf94cd02dd08126131badc1300c249b7bdd6)), para_header_at_relay_header_at_target: Some(HeaderId(44, 0xecf8c174d0db20dbdd650760ca23b9c4ee486830108d3c900d8d63e11dfa6576)), relay_header_at_source: 64, relay_header_at_target: Some(61) }
2024-02-15 14:33:34 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(48, 0x0686db8c1cc6f6183d9f5129d1066daad70c4c1dc49278379d9567ba8c70dcf3)), para_header_at_relay_header_at_target: Some(HeaderId(44, 0xecf8c174d0db20dbdd650760ca23b9c4ee486830108d3c900d8d63e11dfa6576)), relay_header_at_source: 66, relay_header_at_target: Some(61) }
2024-02-15 14:33:46 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(50, 0x2fa75809406173699aa96564f182655eeba00ffa13785819b76b0e4de6036e51)), para_header_at_relay_header_at_target: Some(HeaderId(44, 0xecf8c174d0db20dbdd650760ca23b9c4ee486830108d3c900d8d63e11dfa6576)), relay_header_at_source: 68, relay_header_at_target: Some(61) }
2024-02-15 14:33:58 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(52, 0xbcd120b9b201b94b46d38d1dc47801421115cbd22fe3093849c71ff891aeaedd)), para_header_at_relay_header_at_target: Some(HeaderId(44, 0xecf8c174d0db20dbdd650760ca23b9c4ee486830108d3c900d8d63e11dfa6576)), relay_header_at_source: 70, relay_header_at_target: Some(61) }
2024-02-15 14:34:10 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), para_header_at_relay_header_at_target: Some(HeaderId(44, 0xecf8c174d0db20dbdd650760ca23b9c4ee486830108d3c900d8d63e11dfa6576)), relay_header_at_source: 72, relay_header_at_target: Some(61) }
2024-02-15 14:34:22 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(55, 0xe1be9563069d19dd6038ed26d584f86fd48149c568cf0e3a27a35ba3c667379e)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 74, relay_header_at_target: Some(71) }
2024-02-15 14:34:34 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(57, 0xea1106cd1400b4a825f3dc84633d3b15bf45dc9e72fdc182c3cd2349f47b7c44)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 76, relay_header_at_target: Some(71) }
2024-02-15 14:34:46 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(59, 0xe1b59ca964aa76dfa498ace70814b517ccabe2b1359e546baa5283cdfd690055)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 78, relay_header_at_target: Some(71) }
2024-02-15 14:34:58 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(61, 0x75cee67f60ed70101cdff4b9fec9a16087f05259dcf761308f53158637c6e205)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 80, relay_header_at_target: Some(71) }
2024-02-15 14:35:10 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(62, 0x5994f45f438a71af3220e0c053b77fac5d1602be6a487b01c15288fed3a73f7c)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 82, relay_header_at_target: Some(71) }
2024-02-15 14:35:22 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(64, 0xf32e7d17aeee5ebe0b08c96e33c8263feae068f816017f27b9bb45873d38ef71)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 84, relay_header_at_target: Some(71) }
2024-02-15 14:35:34 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(66, 0xe8a896293bfb64b6619444385c88def9a3c683dc7a903976d844e017582add1a)), para_header_at_relay_header_at_target: Some(HeaderId(62, 0x5994f45f438a71af3220e0c053b77fac5d1602be6a487b01c15288fed3a73f7c)), relay_header_at_source: 86, relay_header_at_target: Some(81) }
2024-02-15 14:35:46 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(68, 0xe9df74fa47ca9bb7d5c42a450358eb890d89c577d1f0dcafb649a1e376be12b1)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 88, relay_header_at_target: Some(71) }
2024-02-15 14:35:58 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(70, 0x85f627c02aa899e4d4ad01eed2f2fa4a71ffaae1ca882eac25a5434b890cff56)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 90, relay_header_at_target: Some(71) }
2024-02-15 14:36:10 +00 TRACE bridge [BridgeHubRococo-to-BridgeHubWestend-on-demand-parachain] Selected new relay state: Idle using old state Idle and data RelayData { required_para_header: 0, para_header_at_target: Some(26), para_header_at_source: Some(HeaderId(71, 0xd43322fcdd09502a51c3099ca965c8e191f220c4238a9eca058e22ecd3d4d1b5)), para_header_at_relay_header_at_target: Some(HeaderId(53, 0x46997431ea2a6ad1ebc597595e006a781666d64ce025ded3f357e35f6218598f)), relay_header_at_source: 92, relay_header_at_target: Some(71) }