[CMake] Remove requirement of NumPy header files (#108465)
NumPy header files were required for building MLIR, however the NumPy
C-API is never used. In other words, NumPy is not a build time
dependency. `numpy`, the python package, is required at runtime for the
python bindings tests. In particular the file
`mlir/python/mlir/runtime/np_to_memref.py` and all tests which may use
it. This commit removes the build time dependency, but the runtime
dependency remains through the `requirements.txt` file.
Co-authored-by: Erick Ochoa <erick@ceci-nest-pas.me>
