Release v19.34.2

Fixed

• A quarantined observer now stays quarantined until an operator clears it or it receives a fresh subscription. Before, a watchdog check, a catch-up or replay job finishing, or the event store subscription check could silently resume it. Completed work still records its progress, so clearing the quarantine resumes from where that work stopped, and for a subscribed observer it also resumes paused jobs and retries failed partitions. Ending quarantine lists exactly what ends a quarantine. (#4440)