Message 395766 - Python tracker

Well, now I've looked at the CPython test failure more closely, and it's in `test.test_venv.EnsurePipTest` where we just download latest pip. 

Their release cadence suggests a new release in July, about 2-4 weeks from now. So I'll wait on adding the DeprecationWarning for passing `None` unless folks ask for it during review, and am happy to wait a few weeks for green CI.