vertex client cache fix

src/helm/clients/vertexai_client.py

@@ -202,6 +202,7 @@ def get_model(model_name: str) -> GenerativeModel:
     def make_request(self, request: Request) -> RequestResult:
         """Make a request"""
         contents = [request.prompt]
+        content_key = request.prompt
 
         # For the multimodal case, build up the content with the media objects of `request.multimodal_prompt`
         if request.multimodal_prompt is not None:
@@ -214,6 +215,7 @@ def make_request(self, request: Request) -> RequestResult:
                 contents.append(
                     Content(role=role_mapping.get(msg["role"], "user"), parts=[Part.from_text(msg["content"])])
                 )
+            content_key = '\n'.join([msg["content"] for msg in request.messages])
 
         parameters = {
             "temperature": request.temperature,
@@ -280,6 +282,7 @@ def do_it() -> Dict[str, Any]:
                 {
                     "model_name": model_name,
                     "prompt": request.prompt,
+                    "content": content_key,
                     **parameters,
                 },
                 request,