Notification Backend Integration: Remove submission.notification.create type from backend return

[SathyaJayabal]

We need to remove submission.notification.create type from backend return as we not longer display submission uploaded notifications.

[SathyaJayabal]

verified on dev

[SathyaJayabal]

#3337 (comment)

@sachin-maheshwari , we need to remove the older submission uploaded notifications from the backend. even though they are not displayed on the front end, it causes the bell icon to be highlighted and shows an empty notifications popup.