ipatests: fix nightly_latest_testing_selinux template
    
    The TestInstallWithoutSudo entry referenced fedora-latest instead
    of testing-fedora for its build dependency. Fix it.
    
    Fixes: https://pagure.io/freeipa/issue/8530
    Signed-off-by: François Cami <fcami@redhat.com>
    Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>