[Build] Deal with mypy/numpy issue (#360)

The latest release of `numpy` (2.5) is shipping type hints which only work with Python 3.12 or later, but we still support earlier Python versions. We configure `mypy` to make its compatibility check against 3.10, so `mypy` gets upset when running a later Python (which will have installed the latest `numpy`). This suppresses checking through `numpy` to avoid this.