Improve primitives typehints

[ElePT]

What should we add?

At the moment, the primitives run() method typehints use collections.abc.Sequence for batches of circuits, parameter values or observables. However, we want to support inputs of type np.ndarray, which don't implement the Sequence protocol (they don't implement count() or index()).

After an internal discussion, it looks like a good solution is to change the typehints from Sequence to Iterable (numpy arrays do satisfy Iterable), and normalize the input to tuple or list for internal use. This would require some changes in type checking/error handling (in particular, in BasePrimitive._validate_circuits).

[1ucian0]

Is any of these https://github.com/Qiskit/qiskit-terra/pulls?q=is%3Apr+label%3Amypy a fix for this issue?

[ElePT]

TL;DR: No

I noticed this issue while reviewing #8263, but considered out of scope for this PR, as it affects the primitive base class, and therefore other implementations of the primitives.