[python3] Update to 3.12.9, drop Windows 7 support - #40996

Based on discord conversation: Tagging depends:vm-update as this needs the Android build container to be on a later Ubuntu than 20.04.

#42749 updated the Android image to Noble.

Unfortunately gobject-introspection:x86-windows looks like a legitimate failure:

D:\installed\x86-windows\tools\python3\python.exe: No module named virtualenv

Unfortunately gobject-introspection:x86-windows looks like a legitimate failure

God I hate this port.

Unfortunately gobject-introspection:x86-windows looks like a legitimate failure

The port uses target python on windows. It also requires setuptools for Python >= 3.12. To get setuptools you need venv. To get venv you need to use x_vcpkg_get_python_packages.
x_vcpkg_get_python_packages doesn't know how to deal with target python.

#43732 (comment)

This build is passing now, does that mean this is good to go?

Ready for review, though I also wanted to add some test ports (I can do it in a follow-up PR).