remove unused import

Change-Id: Ie49216fef5eb13e202fd276fff62e7e20f03b062

Author: MarkDaoust

google/generativeai/client.py

@@ -5,7 +5,6 @@
 import inspect
 import dataclasses
 import pathlib
-import types
 from typing import Any, cast
 from collections.abc import Sequence
 import httplib2