[Python] FixedSizeListType is not considered as a nested type

[hussein-awala]

Describe the bug, including details regarding any error messages, version, and platform.

>>> import pyarrow as pa
>>> pa.list_(pa.int32())
ListType(list<item: int32>)
>>> pa.list_(pa.int32(), 3)
FixedSizeListType(fixed_size_list<item: int32>[3])
>>> pa.types.is_nested(pa.list_(pa.int32()))
True
>>> pa.types.is_nested(pa.list_(pa.int32(), 3))
False

Component(s)

Python