In 5.16 onwards, low priority notifications are displayed to the user in a pop-up but
don't get added to the history.
When a network connection is successfully activated, there's nothing further for the
user to have to know or do; it just works and they start using it. As such, there is
no value to keeping the notification in the history; it's just spam. So, this patch
marks that notification as low priority so it doesn't clutter up the history.