[QUARANTINE] Create Push Rules using signed commits restricts to signed commits

What does this MR do?

Quarantines the test Create Push Rules using signed commits restricts to signed commits (https://gitlab.com/gitlab-org/gitlab/-/blob/master/qa/qa/specs/features/ee/browser_ui/3_create/repository/push_rules_spec.rb#L36)

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

1. ee:instance-parallel
2. ee:relative_url-parallel
3. ee:update-parallel
4. ee:praefect-parallel
5. ee:instance-parallel
6. ee:relative_url-parallel
7. ee:update-parallel
8. ee:praefect-parallel

#354789 (closed)

(This MR was automatically generated by Confiner at 2022-04-14 01:18:24 UTC)