[LI-HOTFIX] Add comment to explain the safety of the brokerEpochSupplier method

[gitlw]

TICKET = N/A LI_DESCRIPTION = Add comment to explain the safety of the brokerEpochSupplier method EXIT_CRITERIA = N/A

More detailed description of your change, if necessary. The PR title and PR message become the squashed commit message, so use a separate comment to ping reviewers.

Summary of testing strategy (including rationale) for the feature or bug fix. Unit and/or integration tests are expected for any behaviour change and system tests should be considered for larger changes.

Committer Checklist (excluded from commit message)

• [ ] Verify design and implementation
• [ ] Verify test coverage and CI build status
• [ ] Verify documentation (including upgrade notes)