Installs `usd-core` without variants, has c++ objects, probably should have platform variants

[vanridal]

latest rez-pip HEAD on main 18/07/2025

OS: Linux

Log:

./rez_pip_venv/bin/python -m rez_pip -p ./test --python-version 3.9 usd-core
INFO     Installing requested packages for Python 3.9.18
INFO     Resolved 1 dependencies for python 3.9.18
INFO     Downloading...
INFO     Downloaded usd-core-25.5.1 to '/tmp/rez-pip-targetnds645f4/wheels/usd_core-25.5.1-cp39-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl' (26913567 bytes)
INFO     Downloaded 1 wheels
INFO     Installing 'usd-core' '/tmp/rez-pip-targetnds645f4/wheels/usd_core-25.5.1-cp39-none-manylinux_2_17_x86_64.manylinux2014_x86_64.whl'
INFO     Creating rez package for usd-core
INFO     Installing usd_core-25.5.1 []
INFO     Created 1 variants and skipped 0

[vanridal]

This might explain why
Two different entries for Root-is-Purelib

cat ./usd_core-25.5.1.dist-info/WHEEL

Wheel-Version: 1.0
Generator: bdist_wheel (0.41.2)
Root-Is-Purelib: true
Tag: cp310-none-manylinux_2_17_x86_64
Tag: cp310-none-manylinux2014_x86_64
Root-Is-Purelib: False