obs-scripting: Replace PySys_SetArgv with recent Python method

[tytan652]

Description

Warning

Only tested on Linux so no runtime link test
Tests on Windows and macOS with various Python is needed

Replace deprecated PySys_SetArgv with recent Python method

TODO:

• Import symbols for runtime link

Closes #13014

Motivation and Context

Gave a try a while ago, now I cleaned it up

How Has This Been Tested?

Only quickly tested on Arch Linux with Python 3.14.5

Types of changes

• Tweak (non-breaking change to improve existing functionality)

Checklist:

• I have read the contributing document.
• My code has been run through clang-format.
• My code follows the project's style guidelines
• My code is not on the master branch.
• My code has been tested.
• All commit messages are properly formatted and commits squashed where appropriate.
• I have included updates to all appropriate documentation.

[RytoEX]

This is a different attempt at #13014 ? If so, my same questions apply.

[tytan652]

This is a different attempt at #13014 ?

I forgot about that PR, yes but with proper support for the runtime codepath.

For run time dependencies, we in theory support Python 3.6+, so it would need to be confirmed if a user can still load/use Python 3.6/3.7 with the original changes. If it is the case that users cannot use Python 3.6/3.7 at runtime with the original changes, then my comment was a note to mergers that "this cannot be merged until we're in a merge window for a major release as this would be a breaking change".

The open question is: does the code in this PR as it was originally or as it is now affect compile-time Python, run-time Python, or both?

In the runtime codepath, if Python < 3.8 is found, python_pre38_init() will be used (with python_pre37_init_threads() if < 3.7).