fix: fix smart contracts api raise with nil sort type

[Naupio]

No description provided.

[Naupio]

before fix:

sorter item without sort_type

query {
  smart_contracts(input: { limit: 10, sorter: [{ sort_value: CKB_BALANCE }] }) {
    entries {
      name
      ckb_balance
    }
  }
}

[Naupio]

after fixed

query {
  smart_contracts(
    input: {
      limit: 10
      sorter: [
        { sort_type: DESC, sort_value: EX_TX_COUNT }
        { sort_type: DESC, sort_value: CKB_BALANCE }
      ]
    }
  ) {
    entries {
      name
      ckb_balance
    }
  }
}

[Naupio]

after fixed if not fill the sort type value will return this message

[Naupio]

pr link: #1301

[alexsupa597]

PR: Magickbase/godwoken-explorer-ui#735

[Naupio]

testnet-prod was deployed @FrederLu

[FrederLu]

Verified.