While the unread messages indicator is updated when starting a new
session because we call _onSourceAdded() on existing sources, we should
also update the do-not-disturb setting which might still be enabled.
https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/1037
let sources = Main.messageTray.getSources();
sources.forEach(source => this._onSourceAdded(null, source));
+ this._sync();
+
this.connect('destroy', () => {
this._settings.run_dispose();
this._settings = null;