Merge conflict on XWiki.Notifications.Code.NotificationAdministration in some cases when upgrading to XWiki 13.7

1. Create an older instance of XWiki (e.g. 12.10.9) with a subwiki (tested on Tomcat 9.0.52)
2. Close the instance
3. Go to the newer instance (e.g. 13.7) and copy/cut the

   [...]webapps\xwiki

   folder and replace it (first delete the old one) in the same location on the older version (no need to copy the data folder since the upgrade will be performed on the same Tomcat (version) configuration)

1. Start XWiki and follow the Distribution Wizard through the upgrade process
2. Go to Wiki Index and click on the previously created subwiki name to start the DW

EXPECTED RESULTS

The upgrade process is completed successfully without errors both on the Main wiki, as well as on subwiki.

ACTUAL RESULTS

A merge conflict is encountered on Main wiki DW as well as on subwiki, related to the page 'XWiki.Notifications.Code.NotificationAdministration'.

While testing the upgrade from XWiki 11.10.13 to 13.7, the respective merge conflict was encountered only on subwiki DW.

The issue could not be reproduced when upgrading to XWiki 13.6.