XWikiGuest avatar from Drawer should lead to a page with some explanations and a link to the login page instead to a non existing page

At the moment, if no user is logged in, opening the Drawer and clicking on XWikiGuest profile picture leads to a non existing page: http://localhost:8080/xwiki/bin/view/XWiki/XWikiGuest.

This is not such a nice place for an user to land on, especially when is placed among the first elements a new user can navigate to and may create confusion.

It would be nice that this would lead to a page that contains some explanations about XWikiGuest profile and why is being displayed here and a link to the login/registration templates, something like:

"This is the XWiki Guest profile which is used for Unregistered users.
In order to have access to all features, you must <Login> or <Register>".

Maybe even include a generic image, like the type displayed just after registration, implemented in XWIKI-22121.