Messages in inbox still show when deleted by creator

[aeharding]

Describe the bug

If creator deletes a comment that shows in your inbox, it will still show the comment. Should say "deleted by creator" or something.

To Reproduce Steps to reproduce the behavior:

1. User A create comment reply to user B
2. User A delete comment
3. User B views inbox
4. See comment content intact

Expected behavior

Should not be visible.