[MM-10645] Remove desktop duration notify props (#8851)

* remove desktop duration notify props

Signed-off-by: Saturnino Abril <saturnino.abril@gmail.com>

* fix test

Signed-off-by: Saturnino Abril <saturnino.abril@gmail.com>

model/user.go

@@ -22,7 +22,6 @@ const (
 	USER_NOTIFY_NONE             = "none"
 	DESKTOP_NOTIFY_PROP          = "desktop"
 	DESKTOP_SOUND_NOTIFY_PROP    = "desktop_sound"
-	DESKTOP_DURATION_NOTIFY_PROP = "desktop_duration"
 	MARK_UNREAD_NOTIFY_PROP      = "mark_unread"
 	PUSH_NOTIFY_PROP             = "push"
 	PUSH_STATUS_NOTIFY_PROP      = "push_status"