[merchant-api] fix: parse API response correctly

* convert to camelCase fields

Author: AndreyMarkinPPC

libs/garf_community/google/merchant/garf_merchant_api/api_clients.py

@@ -46,6 +46,7 @@ def get_response(
     response = client.search(request=merchant_request)
     results = []
     for page in response:
-      for result in page.get('results'):
-        results.append(result)
+      for rows in page.get('results'):
+        for _, row in rows.items():
+          results.append(row)
     return api_clients.GarfApiResponse(results=results)

libs/garf_community/google/merchant/garf_merchant_api/query_editor.py

@@ -13,9 +13,16 @@
 # limitations under the License.
 """Defines MerchantQuery."""
 
+from typing_extensions import Self
+
 from garf_core import query_editor
 
 
+def _to_camel_case(field: str) -> str:
+  first, *others = field.split('_')
+  return ''.join([first.lower(), *map(str.title, others)])
+
+
 class MerchantApiQuery(query_editor.QuerySpecification):
   """Query to Knowledge Graph Search api."""
 
@@ -28,3 +35,12 @@ def __init__(
   ) -> None:
     """Initializes MerchantApiQuery."""
     super().__init__(text, title, args, **kwargs)
+
+  def extract_fields(self) -> Self:
+    for line in self._extract_query_lines():
+      line_elements = query_editor.ExtractedLineElements.from_query_line(line)
+      if field := line_elements.field:
+        self.query.fields.append(
+          _to_camel_case(field) if '_' in field else field
+        )
+    return self