This fixes emitting NotificationClosed for resident notifications
that are clicked, but are not actually destroyed.
This also ensures that we emit NotificationClosed in all cases when
a notification is destroyed, which can happen when:
- a non-resident notification is clicked
- an action is invoked on a non-resident notification
- an application the notification was associated with is focused
- a transient notification is done showing
- a notification was requested to be closed by the application
- a tray icon the notification was associated with is removed
https://bugzilla.gnome.org/show_bug.cgi?id=638071
e9613b0340