size-check: update test Bugzilla URL, blocking image list
    
    Workstation aarch64 is blocking these days, not armhfp. And
    partner-bugzilla is no more, the new trendy test Bugzilla is
    bugzilla.stage.redhat.com (which has Fedora versions over 30,
    so we can drop that workaround).
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>