Add Tx retry in relayer loop

[ancazamfir]

Crate

relayer

Summary

There are some failures in packet Tx that require retries in V0:

• when the timeout height is close to latest chain height, the relayer still builds a recv_packet (as it should) and it is possible that the chain receives it after the timeout, rejecting therefore the transaction.
• during testing, if the user issues the packet-send CLI while the relayer processes previously sent packet, it is possible that both the CLI and the relayer loop use the same account sequence. If the packet_send gets through first, the relayer loop Tx will be rejected.

Post V0 other cases will occur.

Proposal

Add retry in relay_from_events() for all failures.

---

For Admin Use

• Not duplicate issue
• Appropriate labels applied
• Appropriate milestone (priority) applied
• Appropriate contributors tagged
• Contributor assigned/self-assigned