test/udev-test: gracefully exit when imports fail
    
    In Fedora rawhide various perl modules are now available as separate
    packages that are not pulled in by dependencies. If we don't have some
    package, skip the tests.
    
    This ugly code is apparently the way to do conditional imports:
    https://www.cs.ait.ac.th/~on/O/oreilly/perl/cookbook/ch12_03.htm.
    
    (cherry picked from commit d40763838278246e2073d15ca927ee700e583afc)
    
    Related: #1642728
    
    patch_name: 0543-test-udev-test-gracefully-exit-when-imports-fail.patch
    present_in_specfile: true
    location_in_specfile: 543
    squash_commits: true