2d4ba30ba2
Special-casing banners of resident notifications was really a thinly veiled special case for chat notifications, as those were still using the old notification actor which coupled the life-time of the notification to its actor. This is no longer the case, so we can do the sane thing and destroy banners once they are no longer needed. https://bugzilla.gnome.org/show_bug.cgi?id=746343