Allow GoogleAdsToGcsOperator use search_proto_plus() instead of search() method

[ag-q]

There is no way to use search_proto_plus() instead of default search() method in airflow/providers/google/ads/transfers/ads_to_gcs.py without overriding the existing operator.

I mean specifically this line:
rows = service.search(client_ids=self.client_ids, query=self.query, page_size=self.page_size)

The operator should allow you to choose the appropriate method between search() and search_proto_plus(), because there are enum fields in Google Ads that cannot be imported as strings (names) without the search_proto_plus() method.

For now I managed by overriding the default search() method with search_proto_plus(), but it would be great to have the option to choose between these methods in the package.

Apache Airflow version: 2.4.3
apache-airflow-providers-google==8.8.0

[potiuk]

Feel free to contribute it - no issue needed, PR is more than enough.