Diff displayer for extensions is displaying false positives when a page is contained by 2 extensions

How to reproduce:

• install a fresh 7.4.2 using distribution wizard
• make no change on the wiki
• go in the extension manager, in the installed extensions, look for the extension "XWiki Enterprise - UI - Main wiki"
• compute the changes of this extension using the feature added by XWIKI-11506
• in these changes, some pages like XWiki.DocumentTreeTransations.fr , XWiki.DocumentTreeTransations.lv, etc. will appear as being different between the version on the wiki and the version from Document Tree Macro extension.

However, these version of these pages are installed like this on the wiki by the extension org.xwiki.platform:xwiki-platform-index-ui which is also a dependency of XWiki Enterprise - UI - Main wiki. Thus they were installed by XWiki Enterprise - UI - Main wiki so I would not expect them to show up as differences between this extension and the wiki.

Now, beyond the fact that DocumentTreeTranslations.* documents should not be overwritten by the extension org.xwiki.platform:xwiki-platform-index-ui (which is another problem), I think we also have an issue with changes computed for legitimate cases when a page is part of 2 extensions.