Fix error handling

[salman01zp]

Summary of changes

• Return the error back to the handler
• Partial Fixed for EVM by #515

Earlier since it didn't return any error, it just skipped that proposal making it difficult to debug. But now it returns an error to handle_events_with_retry and eventually exits after max_retries with error message.

{"timestamp":"2023-05-26T09:06:19.075018Z","level":"DEBUG","message":"sending proposal to DKG runtime","nonce":"Nonce(1)","resource_id":"000000000000d3f6f733d3d38e4eb94f68c8b3d673ff5934644c010000000d06","src_chain_id":"Evm(3333)","proposal":"000000000000d3f6f733d3d38e4eb94f68c8b3d673ff5934644c010000000d06c1922f9e000000012b33c05921e92b32e68a04d23557ec38c0ba197b31eee5392f1e5fc8bfcdb014000000000000ce372dba63a7acc4811bc5d8df82d112fa2c4adb010000000d05","target":"webb_proposal_signing_backends::dkg","spans":[{"address":"0xce37…4adb","tag":"VAnchor Contract Watcher","name":"run"},{"name":"handle_event"}]}

{"timestamp":"2023-05-26T09:06:19.181700Z","level":"DEBUG","message":"sending proposal to DKG runtime","nonce":"Nonce(1)","resource_id":"000000000000d3f6f733d3d38e4eb94f68c8b3d673ff5934644c010000000d06","src_chain_id":"Evm(3333)","proposal":"000000000000d3f6f733d3d38e4eb94f68c8b3d673ff5934644c010000000d06c1922f9e000000012b33c05921e92b32e68a04d23557ec38c0ba197b31eee5392f1e5fc8bfcdb014000000000000ce372dba63a7acc4811bc5d8df82d112fa2c4adb010000000d05","target":"webb_proposal_signing_backends::dkg","spans":[{"address":"0xce37…4adb","tag":"VAnchor Contract Watcher","name":"run"},{"name":"handle_event"}]}

{"timestamp":"2023-05-26T09:06:19.287636Z","level":"DEBUG","message":"sending proposal to DKG runtime","nonce":"Nonce(1)","resource_id":"000000000000d3f6f733d3d38e4eb94f68c8b3d673ff5934644c010000000d06","src_chain_id":"Evm(3333)","proposal":"000000000000d3f6f733d3d38e4eb94f68c8b3d673ff5934644c010000000d06c1922f9e000000012b33c05921e92b32e68a04d23557ec38c0ba197b31eee5392f1e5fc8bfcdb014000000000000ce372dba63a7acc4811bc5d8df82d112fa2c4adb010000000d05","target":"webb_proposal_signing_backends::dkg","spans":[{"address":"0xce37…4adb","tag":"VAnchor Contract Watcher","name":"run"},{"name":"handle_event"}]}

{"timestamp":"2023-05-26T09:06:19.288137Z","level":"ERROR","message":"Error while handling the event","e":"SubxtError(Metadata(IncompatibleCallMetadata(\"DKGProposals\", \"acknowledge_proposal\")))","chain_id":"3333","target":"webb_event_watcher_traits::evm::event_watcher","spans":[{"address":"0xce37…4adb","tag":"VAnchor Contract Watcher","name":"run"}]}

Reference issue to close (if applicable)

• Closes #518

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Code Checklist

• [x] Tested
• [ ] Documented