[API] notifcations API returns 500 if comment was deleted

[qwerty287]

Gitea Version

1.16.0

How are you running Gitea?

built from source, from cli

Can you reproduce the bug on the Gitea demo site?

Yes

Description

The notifications API (api/v1/notifications) returns a 500 internal server error if any notification addresses a comment that was deleted.
...pi/v1/notify/user.go:85:ListNotifications() [E] InternalServerError: GetCommentByID [193] for issue ID [53]: comment does not exist [id: 193, issue_id: 0]

[zeripath]

OK so the problem here is that NotificationList.LoadAttributes() is not fault tolerant and will return whenever there is an error.