The user picker used by the List of Users property doesn't show the common name differentiator

Steps to reproduce:

• Follow https://extensions.xwiki.org/xwiki/bin/view/Extension/User%20Module/API/#HConfiguration to configure the user.display.qualifierProperty
• create a class with a property of type List of Users (you can use AppWithinMinutes for this)
• create a page with an object of this class and check the user picker

The configured qualifierProperty is not shown as hint for the user suggestions. It is shown only if you use the user picker without a List of Users property, as per https://www.xwiki.org/xwiki/bin/view/Documentation/DevGuide/FrontendResources/AutoSuggestWidget/#HSuggestUsers .