Email notifications events description do not display the user avatar anymore

Steps to reproduce

1. Login as Admin
2. (Optional): set a custom avatar to Admin profile
3. Setup the Mail Sending on the instance
4. Create an user (e.g. U1) with a valid email address
5. Login as the user
6. Click on the Notifications Bell and turn ON all Watch Notification Toggles
7. Login as Admin
8. Create a page (e.g. 'Pag1') and save it
9. Edit the page again, add some content and save it
10. Comment on the page
11. Go to <server>/xwiki/bin/view/Scheduler/ and click on "Trigger" button for the 'Notifications daily email' job
12. Observe the notification events in the email received by the user

Expected results

The user's avatar (who performed the respective events) is displayed in the notifications events description from the mail received by the user.

Actual results

The events description do not display the user (Admin) avatar, is displayed only the name of the user instead followed by a link to the user's profile (which in XWiki 15.10 is underlined and appears in a darker blue compared to 15.7 for ex, where the link to the profile is not underlined and it's a lighter blue, tested on Firefox 121), see the attached screenshots.

The issue reproduces as well on XWiki 15.10.3 and could not be reproduced on XWiki 15.7, 15.5.4 or 14.10.20 (where XWIKI-21589 was not present).