User event status is not cleaned when deleting a user

The scenario to notice it in 12.6 is to delete a user having unread notifications and then create a new user with the exact same id: the new user get the previous user notifications.

It's less visible before 12.6 because in post filtering the UI is not searching for events at all when there is no configured filter and then each filter in the user preferences is associated with the date at which it was created. The statuses are still there but the data prevent them to show up, not great for database space but unnoticeable unless you request the database directly.