Notification events contain invalid alt attribute on user profile picture

Steps to reproduce :

• Start from a fresh 13.10.7
• Using the default Admin, edit any page with a major edit
• Go in the profile of the user
• The user activity stream should have at least 1 entry. Inspect the user profile picture next to the user name of this entry

Expected : This image has the user first name and last name as alt attribute.

Actual : The image has an alt attribute which contains escaped HTML like this :

<span class="notification-event-user">
  <img src="/xwiki/bin/skin/resources/icons/xwiki/noavatar.png?cache-version=1656399606747" alt="<span class=&quot;wikilink&quot;><a href=&quot;/xwiki/bin/view/XWiki/Admin&quot;>Administrator</a></span>"/>
  […]
</span>

This makes it so that when the user profile picture fails to load, the HTML code within the alt of the user profile picture gets displayed.