Add integration test for ack packets getting relayed properly

## Summary

At the moment there are some integration tests for the relayer, but some cases are not covered.

Following issue https://github.com/informalsystems/hermes/issues/2920 the addition of a test checking that the acknowledgment messages, and the full relaying of messages, is required.

## Proposal

Addition of tests covering the relaying of a message and checking that everything is correctly relayed to the source and destination chain.

## Acceptance Criteria

Improve current integration tests for relayer or adding new tests which cover the missing scenario.

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#### For Admin Use

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Start by reading issue #2920 and locating the existing relayer integration tests in the repository. Trace how acknowledgment packets and complete message relaying are currently exercised, then add coverage for the missing source-to-destination scenario. Done means the tests verify acknowledgments and full relaying on both chains.

Written by the indexing model from the issue text.