Use the full content to display the configuration

[acotiuga]

In XWiki 8.4, the configuration form uses the half class and the form is using only half of the content. This was improved in XWiki 9.2-rc-1 (xwiki/xwiki-platform@40129b9#diff-a5e2bdfae0d64b99e930426d8e592300L257).
The idea is to remove the class and, when the Active Directory app will use XWiki 9.2 or greater, the code added to fix the current issue to be also removed.

Half:

Full: