Comments that are deleted should have that event removed from the log

[kkrysiak]

This log says a user made a comment but there are no comments on the entity. https://civicdb.org/events/genes/52/summary/variants/621/summary/evidence/1582/talk/log

Deletes should remove all activity. However, this action should be limited to a time period or if any comments are added after the users comment. This will prevent threads having discussion in the middle removed while maintaining a user's ability to fix mistakes they noticed quickly.