Fix: Remove orphaned return statement in test_campaign_report_to_csv.py

This commit removes a stray `return row` line from
`examples/misc/tests/test_campaign_report_to_csv.py`.
This line was a remnant from the removal of the old `_create_mock_row`
helper method and was causing a `NameError: name 'row' is not defined`
during test collection, causing all tests in the file to fail.

Author: google-labs-jules[bot]

examples/misc/tests/test_campaign_report_to_csv.py

@@ -108,7 +108,6 @@ def mock_get_type_side_effect(type_name):
     # If it were to be kept, it would need to use the new helper classes or be for a different purpose.
     # For now, removing it to avoid confusion with the new MockCSVRow.
     # def _create_mock_row(...):
-        return row
 
     @mock.patch("builtins.open", new_callable=mock.mock_open)
     def test_main_success_with_headers(self, mock_open_file):