Fix EZP-23580: FOSHttpCache always matches default site with urielement matcher

> https://jira.ez.no/browse/EZP-23580

Bug introduced by #1025 ([EZP-22400](https://jira.ez.no/browse/EZP-22400)).
SiteAccess matching was always triggered for user hash requests, which should never happen.

This PR fixes it.
Tests: Unit test added.