Fix style issues in exception interceptor

Author: BenRKarl

google/ads/googleads/interceptors/exception_interceptor.py

@@ -19,7 +19,7 @@
 so it translates the error to a GoogleAdsFailure instance and raises it.
 """
 
-from typing import Any, Callable, Union
+from typing import Callable, Optional, Union
 
 from google.protobuf.message import Message
 import grpc