pytest: ignore unraisable exception errors
    
    Tests fail with an unraisable exception error from pytest on
    EPEL 9, but not Rawhide or F37. This feels a lot like somebody
    else's problem and I don't want to worry about it too much, so
    let's just ignore it. I might report it to upstream, but dunno
    if they'd do anything about it.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>