URI2RepositoryMapping does not accept .html anymore

Steps to reproduce

1. Suppose you have two separeted language trees, e.g. site-de and site-fr
2. Configure a site with mapping for the sites:

• /de -> /site-de
• /fr -> /site-fr

1. Open the site home-page with /de.html or /fr.html will not use the correct site, which may results in a wrong theme
2. Open the site /de or /fr works as accepted

Expected results

Correct site is used for a URIPrefix even if it ends with `.html` instead of `/`

Actual results

Wrong site definition is used, and thus wrong theme is displayed

Workaround

With an additional site-mapping e.g. `for /de.html` this can be fixed, but it's not a nice solution, since it could blow up the configuration

Development notes

This bug was introduced with MAGNOLIA-8234 and this commit: https://git.magnolia-cms.com/projects/PLATFORM/repos/main/commits/3c965c8b66b4e02bc0c40b7c1f96d45b9b888cef

This is a Major Bug for us, because of the log4shell exploit, since some production environments are affected after rolling out the new magnolia version