Test macos-latest, 3.9 workflow builds fail (infrastructure issue)

[cosenal]

The test (macos-latest, 3.9) builds are failing because of https://github.com/actions/setup-python/issues/696

Possible workarounds (inspired by what others are doing):

• exclude this combination of os and python version from the test matrix
• pin to an older version of mac os (pre-arm64 arch)
• ignore the issue in the builds until it's fixed upstream

[cosenal]

This was fixed by https://github.com/actions/python-versions/pull/264 Tested in our builds and it's working again now: https://github.com/unitaryfund/mitiq/actions/runs/8821438712/job/24286681768