MWPS fix appears to break merge request approvals

We urgently merged in d78d2ba2 to fix Merge When Pipeline Succeeds (MWPS) on GitLab.com.

However, this seems to have broken merge request approvals: https://gitlab.com/gitlab-org/gitlab-ee/builds/9067546

If I revert that commit, things work fine.

You must test against 8-16-stable-ee.