Backport py.exe warnings

[zooba]

In 3.14, py.exe will warn about the PyManager subcommands being used (unless there's actually a file to launch). We should backport these so that users who update 3.13 (and don't use the old installers to get 3.14) will also see the warnings.

Linked PRs

• [3.13] gh-133512: Adds warnings to py.exe launcher about subcommands belonging to Python install manager #133514