Skip test that hates old Python in CI

[adamnovak]

This sweeps #5501 under the rug by skipping this new test in the environments it doesn't succeed in for reasons we can't reproduce.

I'm not sure if we'll still see flaky failures of test_run_and_cancel_workflows if it wins the race naturally and winning the race means a SYSTEM_ERROR in CI on Python <3.14.

Changelog Entry

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• PR submitter writes their recommendation for a changelog entry here

Reviewer Checklist

• Make sure it is coming from issues/XXXX-fix-the-thing in the Toil repo, or from an external repo.
  • If it is coming from an external repo, make sure to pull it in for CI with:

    contrib/admin/test-pr otheruser theirbranchname issues/XXXX-fix-the-thing
    

  • If there is no associated issue, create one.
• Read through the code changes. Make sure that it doesn't have:
  • Addition of trailing whitespace.
  • New variable or member names in camelCase that want to be in snake_case.
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  • New features without tests.
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• Make sure the PR passed tests, including the Gitlab tests, for the most recent commit in its branch.
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