[QUARANTINE] Plan Epics milestone dates API updates epic dates when deleting milestones

What does this MR do?

Quarantines the test Plan Epics milestone dates API updates epic dates when deleting milestones (https://gitlab.com/gitlab-org/gitlab/-/blob/master/qa/qa/specs/features/ee/api/2_plan/epics_milestone_dates_spec.rb#L86)

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

1. e2e:package-and-test-results
2. e2e:package-and-test-results
3. e2e:package-and-test-results

#375942 (closed)

(This MR was automatically generated by Confiner at 2022-10-01 02:10:04 UTC)