typing: Cast transpose to ArrayLike

Sonnet 4's summary:

> The mypy error occurred because the transpose() method on line 659 was
> returning a value that mypy inferred as Any, while the function signature
> declared it should return ArrayLike. Mypy's no-any-return rule flags when
> you return an Any value from a function with a specific return type annotation.

Author: matthewfeickert

src/pyhf/tensor/numpy_backend.py

@@ -656,4 +656,4 @@ def transpose(self, tensor_in: Tensor[T]) -> ArrayLike:
 
         .. versionadded:: 0.7.0
         """
-        return tensor_in.transpose()
+        return cast(ArrayLike, tensor_in.transpose())