updated tests to verify usage of previous_response_id and conversation

Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

llama_stack/log.py

@@ -30,6 +30,7 @@ CATEGORIES = [
     "tools",
     "client",
     "telemetry",
+    "openai",
     "openai_responses",
     "openai_conversations",
     "testing",

llama_stack/providers/inline/agents/meta_reference/responses/openai_responses.py

@@ -230,6 +230,11 @@ class OpenAIResponsesImpl:
         if shields is not None:
             raise NotImplementedError("Shields parameter is not yet implemented in the meta-reference provider")
 
+        if conversation is not None and previous_response_id is not None:
+            raise ValueError(
+                "Mutually exclusive parameters: 'previous_response_id' and 'conversation'. Ensure you are only providing one of these parameters."
+            )
+
         if conversation is not None:
             if not conversation.startswith("conv_"):
                 raise InvalidConversationIdError(conversation)