MyPy fails with new numpy dtype type hints

### Description

In #7792 mypy started failing, likely due to picking up new numpy versions. 

I marked `pymc/sampling/mcmc.py` as failing type-hints for the purpose of the CI:

> pymc/sampling/mcmc.py:837: error: Argument "random_seed" to "init_nuts" has incompatible type "list[signedinteger[_64Bit]]"; expected "int | Sequence[int] | ndarray[Any, Any] | None | None"