tests: webui: Update vendored qunit
    
    Updated qunit to latest supported version from
    https://code.jquery.com/qunit.
    
    See https://qunitjs.com/intro/#release-channels for details.
    
    Related: https://pagure.io/freeipa/issue/9329
    Signed-off-by: Stanislav Levin <slev@altlinux.org>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>