XWIKI-10717: The wysiwyg editor configuration doesn't fallback on the main wiki when local configuration document is missing
* Make sure the class reference points to the main wiki in case of a fallback.

(cherry picked from commit 63215e3f0d9fde08a53ca40e68cc70808cfbf95d)

Conflicts:
	xwiki-platform-core/xwiki-platform-wysiwyg/xwiki-platform-wysiwyg-server/pom.xml

(cherry picked from commit 88b34f0a78a86bb9b66d4717691062b90d879d7b)