fix(mcp_tool_registration_service): add warning for messages with missing role during conversion

Author: Johan Broberg

libraries/microsoft-agents-a365-tooling-extensions-agentframework/microsoft_agents_a365/tooling/extensions/agentframework/services/mcp_tool_registration_service.py

@@ -188,6 +188,11 @@ def _convert_chat_messages_to_history(
 
         for msg in chat_messages:
             message_id = msg.message_id if msg.message_id is not None else str(uuid.uuid4())
+            if msg.role is None:
+                self._logger.warning(
+                    f"Skipping message {message_id} with missing role during conversion"
+                )
+                continue
             role = msg.role.value
             content = msg.text if msg.text is not None else ""