Quarantine pipeline subscriptions test suite

What does this MR do and why?

We disabled a flaky spec yesterday, but it looks like the full suite is affected. We have a suspect MR that causes the flakiness but the person is OOO and communicating with the stakeholders takes some time.

Related Issue: #504369 (closed)

Latest Incident: gitlab-org/quality/engineering-productivity/master-broken-incidents#9376 (closed)

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