Database Tree property changes are not saved anymore in object mode

Steps to reproduce:
1. Create a class with a Database Tree property
2. In the Database Tree property set the XWiki Class Name  field to a class full name ( "XWiki.XWikiUsers")
3. Save the class, generate sheet and template
4. Create a page containing the new object
5. Try to check and uncheck the values in both Edit and Edit Object modes, then save the document.

Expected: the changes should be saved in both modes
Actual: the changes are not saved in Edit Object mode

mflorea explains the reason:
The regression was actually introduced by XWIKI-17174 . treeview.vm, which is used to display the database tree list property using a tree, has some inline script tag.
This script tag handles the save. Starting with XWIKI-17174 (13.1RC1) the object editor loads the form to edit a particular object asynchronously, by requesting the HTML and injecting it in the current page. The problem is that the inline script tag is lost in this process (voluntarily). See https://github.com/xwiki/xwiki-platform/blob/master/xwiki-platform-core/xwiki-platform-web/xwiki-platform-web-war/src/main/webapp/resources/js/xwiki/editors/dataeditors.js#L383 .
The solution would be to extract the inline script in a separate file.