logger and event emitter methods should return Result

[Farhad-Shabani]

Context

Hosts implementing ibc-rs, In certain situations:

• May need to convert an IbcEvent or a log message into a local event or log type specific to their environment. However, this conversion process may encounter failures.
• Likewise, when attempting to store events or logs, there may be instances where the storage operation results in an error.

To accommodate hosts in handling failures according to their preferences in either of these scenarios,emit_ibc_event and log_message methods should return the Result<(), ContextError> type.