snowbridge: improve destination fee handling to avoid trapping fees dust #1472

Job	Run time
preflight / preflight	45s
test-frame-ui	31m 8s
test-full-crypto-feature	2m 33s
cargo-check-all-crate-macos	10m 58s
cargo-check-benches (master)	25m 45s
cargo-check-each-crate (1)	16m 46s
cargo-check-benches (current)	27m 40s
cargo-check-each-crate (2)	18m 26s
test-node-metrics	8m 11s
cargo-check-each-crate (3)	4m 51s
cargo-check-each-crate (4)	14m 11s
cargo-check-each-crate (5)	21m 46s
cargo-check-each-crate (6)	13m 46s
cargo-check-each-crate (7)	25m 13s
test-frame-examples-compile-to-wasm	2m 59s
test-deterministic-wasm	6m 41s
check-tracing	2m 24s
check-metadata-hash	5m 55s
cargo-hfuzz	9m 40s
node-bench-regression-guard	12s
All test misc tests passed	1s
	4h 9m 51s

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