desktop_vt: hackaround 'tty?' problem on F31
    
    On F31 update tests, desktop_vt is broken because the 'ps -C'
    command is showing 'tty?' as the tty on which Xwayland/Xorg is
    running. Let's try using loginctl as a workaround for this.
    This ordering of commands should ensure the ps -C output takes
    precedence when it's correct.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>