panels: Add X-GNOME-UsesNotifications to several desktop files

gnome-settings-daemon emits notifications related to these four control
panels. If we add X-GNOME-UsesNotifications to their desktop files, the
user will be able to control the notifications.

Signed-off-by: Philip Withnall <>
11 jobs for power-notifications in 4 minutes and 48 seconds (queued for 3 minutes and 23 seconds)