Use dynamic %_prefix value when matching files for python(abi) provides
    
    See https://lists.fedoraproject.org/archives/list/packaging@lists.fedoraproject.org/thread/UFKUM5UKCTNGIT3KJVYEI5VXPI23QMBN/
    
    Flatpak builds redefine %_prefix and the dependencies should remain present.
    
    Also get rid of one useless ^ and prep the pattern for two digit Python major versions.
    
    Add a test that tests that we match our default %_prefix (was the case even before this commit).