Re-approvals only applied after successful CI run

Created by: benjamb

There is a comment related to this within marge/job.py, including for context:

# Re-approve the merge request, in case us pushing it has removed
# approvals. Note that there is a bit of a race; effectively
# approval can't be withdrawn after we've pushed (resetting
# approvals) and CI runs.

Occasionally CI may fail due to transient network issues that are unrelated to the change made. In this case, Marge will error out and not bother attempting to reapply any approvals. GitLab doesn't remove approvals on CI failure, so it doesn't quite make sense that this happens with Marge.

This also applies to any potential exception that might occur between the force push and applying approvals, we need to restart marge and then manually approve again.

I'm unaware as to whether there is a historical reason for why approvals are reapplied when they are, but could they no be applied immediately after the rebase?