XAR extension import fails to register extension in farm virtual installation repository

Steps to reproduce:

1. Being XWiki built-in XWiki user import any XAR extension to XWiki
2. Navigate to Extension Manager and find imported extension in installed tab
3. Try to install on farm such extension

Actual result

Extension will be installed on farm, but install log will contain one error

Installed extension [ ] is not properly registered in the virtual XAR installed extensions repository

Expected result

No errors are logged in the installation log.

Note

Originally noticied this error on local Tomcat/PostgreSQL XWiki 18.4.0, also checked on local demo Jetty/HSQLDB 17.10.9. I haven't noticied any functional issue with XAR extension that I installed on farm.
This was introduced in XWIKI-14188 https://github.com/xwiki/xwiki-platform/blob/c9c3dbe7afeaecd0bacc6ea49edf066de3bf7857/xwiki-platform-core/xwiki-platform-extension/xwiki-platform-extension-handlers/xwiki-platform-extension-handler-xar/src/main/java/org/xwiki/extension/xar/internal/handler/XarExtensionPlan.java#L88-L92