Changes

ticdc: Remove redundant skip_if_only_changed from mysql integration test (#3873)

This PR addresses an issue where the
`pull-cdc-mysql-integration-light-next-gen` presubmit job was being
skipped incorrectly due to the `skip_if_only_changed` directive.

The `skip_if_only_changed` directive is intended to prevent jobs from
running if only certain files have been modified, which is not the
desired behavior for this specific integration test. By commenting out
this directive, we ensure that the
`pull-cdc-mysql-integration-light-next-gen` job will always run when
triggered, regardless of the files changed.

Changes:

* Commented out the `skip_if_only_changed` directive for the
`pull-cdc-mysql-integration-light-next-gen` presubmit job.

Signed-off-by: tenfyzhong <tenfy@tenfy.cn>
 (commit: e316ec2)