fix(generator): rename requests import to request to match api-core

Author: hebaalazzeh

packages/gapic-generator/gapic/templates/%namespace/%name_%version/%sub/_compat.py.j2

@@ -3,7 +3,7 @@
 import uuid
 
 try:
-    from google.api_core.gapic_v1.requests import setup_request_id  # type: ignore
+    from google.api_core.gapic_v1.request import setup_request_id  # type: ignore
 except ImportError:  # pragma: NO COVER
     # TODO(https://github.com/googleapis/google-cloud-python/issues/17813): Remove this fallback when google-api-core >= 2.26.0 is the minimum required version.
     def setup_request_id(request, field_name: str, is_proto3_optional: bool):  # pragma: NO COVER