Send notification via GioApplication, not ashpd

Using ashpd I get `Invalid client serial` too many times.
At least now the notifications keep showing, even if ashpd
is still used to monitor network changes, which could still
stop working arbitrarily after `Invalid client serial`

data/com.ranfdev.Notify.desktop.in.in

@@ -10,3 +10,4 @@ Keywords=Gnome;GTK;
 # Translators: Do NOT translate or transliterate this text (this is an icon file name)!
 Icon=@icon@
 StartupNotify=true
+X-GNOME-UsesNotifications=true