Merge conflict when adding content after a user leaves the Realtime Collaboration

Preconditions: Enable realtime collaboration for the WYSIWYG editor

• As Admin click on Drawer > Administer Wiki > Editing > WYSIWYG Editor
• Remove (uncheck) the "xwiki-realtime" from the list of disabled plugins in the CKEditor administration section
• Click on the Save button

Steps to reproduce:

1. As a simple user (user01) edit any page
2. Open a new private (incognito) browser window and login with another simple user (user02)
3. Access the same page and edit it, forcing the lock
4. Add some text
5. Switch to the window of the first user (user01) and add some text
6. Click Save & View
7. Switch back to the private window of the second user (user02)
8. Add some text
9. Click Save & View

Expected results: The entire content is saved.

Actual results: ** The Version conflict message box appears.