This is the same case as
LPS-103448 except instead of deleting the entire page comment, simply remove the mention from the comment.
When user A mentions user B in a comment, they system sends a notification to user B.
- Add a new user
- Add a page fragment
- Add a comment in the page fragment, mentioning the user and save
- Edit the comment: simply remove the mention from the comment
- Log in as new user
- Assert notification no longer applies to use