When stuck operations are removed in DC, users should be notified

Some long-running tasks submitted by users (e.g. re-indexing, user anonymization, bulk issue edit, etc.) can become stuck in Jira Data Center, when the node that was executing them crashes or is shut down.

Jira can clean up those (since https://jira.atlassian.com/browse/JRASERVER-66204). However, only a log message is added when such task is cleaned.

It is very likely that the person that submitted the task does not have access to logs or simply does not (want to) monitor them all the time. Jira should notify the user that submitted the task that is being cleaned up about doing so, to allow them to react - e.g. by re-running the operation.

This could be an in-product flag message, an email or some other way.