Fix HTTP 404 when calling Audit.QueryWithPageProvider by non admins

The operation Audit.QueryWithPageProvider is restricted to admins only thanks to this contribution

However WebUI makes a call by default to this operation though the component "nuxeo-audit-page-provider" (called when no docId is provided) and it generates HTTP 404 errors which bother the monitoring of customers.

This ticket is to add a condition which does not call the operation if the current user is not an admin.