install_optional_packages.py fails on windows.

[benoithudson]

On Win11/x86, Python 3.11, running either in git bash or powershell, the install_optional_packages.py --all chugs and chugs, and then fails.

• The techvar assets show up. No problem here.
• The baked procedural assets show a success message, and take the amount of time you'd expect for downloading all that data, but no files appear on disk that I can find.
• The texture pack download errors out fairly quickly with a MemoryError. No files appear.

The same invocation works perfectly on macos.