refactor(gemini): 🔨 remove redundant model and project fields from request payload

The `model` and `project` parameters were being incorrectly included at the top level of the request payload. These fields are not part of the Gemini API request body structure and should only be used for endpoint construction or authentication context.

src/rotator_library/providers/gemini_cli_provider.py

@@ -1438,8 +1438,6 @@ class GeminiCliProvider(GeminiAuthBase, ProviderInterface):
 
         # Build request payload
         request_payload = {
-            "model": model_name,
-            "project": project_id,
             "request": {
                 "contents": contents,
             },