Quarantining test related to merge request in push_options_mwps_spec

What does this MR do?

Quarantining a flaky test which is due to a race condition in merge when pipeline succeeds as per #346425 (comment 1338213161)

Once the fix for #300353 (closed) has been merged, this test can be de-quarantined

E2E Test Failure issue(s)

Failure in api/3_create/merge_request/push_opti... (#346425)

Check-list

• General code guidelines check-list
  • Code review guidelines
  • Style guides
• Quarantine test check-list
  • Follow the Quarantining Tests guide.
  • Confirm the test has a quarantine: tag with the specified quarantine type.
  • Note if the test should be quarantined for a specific environment.
  • (Optionally) In case of an emergency (e.g. blocked deployments), consider adding labels to pick into auto-deploy (Pick into auto-deploy priority1 severity1).
• Dequarantine test check-list
  • Follow the Dequarantining Tests guide.
  • Confirm the test consistently passes on the target GitLab environment(s).
• To ensure a faster turnaround, ask in the #quality_maintainers Slack channel for someone to review and merge the merge request, rather than assigning it directly.