Follow-up from "Resolve "Squash commit message does not honor regex settings""
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The following discussion from !98686 should be addressed:
- [ ] @hfyngvason started a [discussion](https://gitlab.com/gitlab-org/gitlab/-/merge_requests/98686#note_1116479981): (+1 comment)
> Thanks @j.seto! The code looks good, but I am wondering why this was needed in the first place. I would have expected all git access to be subject to the same checks (for example, [this code](https://gitlab.com/gitlab-org/gitlab/-/blob/3eb5d6d1c81705076015d2110acb91e61cbbbe98/ee/lib/ee/gitlab/checks/push_rules/commit_check.rb#L43) also validates commit messages), but evidently merge request merges implement their own set of validations. This seems bound to lead to further inconsistencies such as here (and I bet we already have several).
>
> Do you know why we have this duplication?
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