display: Stop night light dialog being destroyed twice
The night light dialog is both markes as "destroy_with_parent" and explicitly destroyed in the panel. Drop one of these.
Causes the warning after opening the dialog then closing the app: (gnome-control-center:19887): Gtk-CRITICAL **: 11:00:01.370: gtk_widget_destroy: assertion 'GTK_IS_WIDGET (widget)' failed
This bug was introduced in ed36688c