[Enhancement] Simplify messageStore sendMessageBackHook assignment by removing null check

[mxsm]

Before Creating the Enhancement Request

• I have confirmed that this should be classified as an enhancement rather than a bug/feature.

Summary

Motivation

Simplify messageStore sendMessageBackHook assignment by removing null check

Describe the Solution You'd Like

remove

Describe Alternatives You've Considered

not need

Additional Context

No response