[QUARANTINE] [nightly] Create Merge requests when merging once behaves like merge when pipeline succeeds merges after pipeline succeeds

What does this MR do?

Quarantines the test Create Merge requests when merging once behaves like merge when pipeline succeeds merges after pipeline succeeds (https://gitlab.com/gitlab-org/gitlab/-/blob/master/qa/qa/specs/features/browser_ui/3_create/merge_request/merge_when_pipeline_succeeds_spec.rb#L107)

This test has been found by Confiner to have failed 8 times, which exceeds the threshold of 3 times.

1. ee:update
2. ce:upgrade
3. ee:instance-image
4. ee:instance-image-slow-network
5. ee:update
6. ce:upgrade
7. ee:instance-image
8. ee:nplus1-instance-image

#397495

(This MR was automatically generated by Confiner at 2023-03-20 01:17:48 UTC)