use `skip_pyc_compilation` in pixi-packages

[lucascolley]

numpy/numpy#31558

This cuts a few valuable minutes off the time taken to build tsan-freethreading NumPy against tsan-freethreading CPython (see numpy/numpy#31558). Maybe it is a good idea for the other build variants too, not sure.

Linked PRs

• gh-152317: pixi-packages: skip_pyc_compilation for tsan-freethreading package #152318