Report notifs visible for people who aren't admin/mod any more

In !2912 (merged) notifications for reports were introduced. When someone is demoted from admin/moderator, the notifications are still there.

When someone isn't mod nor admin any more, they shouldn't be able to see these notifs any more. Either the notifs should be filtered from the response, or the notifs should be removed when someone looses admin/moderator status and isn't otherwise an admin/moderator any more.

Related pleroma-fe!1322 (merged)