Fix syncing issue with Notification statuses:

The timeout_notifications job runs daily and does not correctly
update both the status fields to keep them in sync.

tests/app/celery/test_scheduled_tasks.py

@@ -155,9 +155,15 @@ def test_update_status_of_notifications_after_timeout(notify_api, sample_templat
             created_at=datetime.utcnow() - timedelta(
                 seconds=current_app.config.get('SENDING_NOTIFICATIONS_TIMEOUT_PERIOD') + 10))
         timeout_notifications()
+
         assert not1.status == 'temporary-failure'
+        assert not1._status_fkey == 'temporary-failure'
+
         assert not2.status == 'technical-failure'
+        assert not2._status_fkey == 'technical-failure'
+
         assert not3.status == 'temporary-failure'
+        assert not3._status_fkey == 'temporary-failure'
 
 
 def test_not_update_status_of_notification_before_timeout(notify_api, sample_template):