ipatests: fix test_idp
    
    The test is calling su -c "sudo yum list yum" keycloakuser
    to ensure that keycloakuser is allowed to execute the yum command.
    
    On fedora 42 and above, the yum package does not exist any more.
    Replace with a call to yum list sssd-client as the package
    sssd-client is always installed on our test machines.
    
    Fixes: https://pagure.io/freeipa/issue/9769
    Signed-off-by: Florence Blanc-Renaud <flo@redhat.com>
    Reviewed-By: Francisco Trivino <ftrivino@redhat.com>