TYP: add None to __getitem__ in numpy.array_api (#25022)

Closes gh-24982

Original NumPy Commit: 3c853e149d5021a377dbe985ecd06b201ff3de46

Author: Illviljan

array_api_strict/_array_object.py

@@ -542,7 +542,11 @@ def __ge__(self: Array, other: Union[int, float, Array], /) -> Array:
     def __getitem__(
         self: Array,
         key: Union[
-            int, slice, ellipsis, Tuple[Union[int, slice, ellipsis], ...], Array
+            int,
+            slice,
+            ellipsis,
+            Tuple[Union[int, slice, ellipsis, None], ...],
+            Array,
         ],
         /,
     ) -> Array: