Webui tests: new idrange now requires base RID
    
    Now that SID are always generated, the creation of a new
    local idrange is refused if baserid is missing.
    
    Related: https://pagure.io/freeipa/issue/8995
    Signed-off-by: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Christian Heimes <cheimes@redhat.com>
    Reviewed-By: Rob Crittenden <rcritten@redhat.com>
    Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>