do not add user oid to tracing

Author: lusu-msft

sdk/agentserver/azure-ai-agentserver-core/azure/ai/agentserver/core/server/base.py

@@ -105,6 +105,8 @@ def set_user_info_to_context_var(self, request) -> Optional[UserInfo]:
         if user_info:
             ctx = request_context.get() or {}
             for key, value in user_info.to_dict().items():
+                if key == "objectId":
+                    continue  # skip user objectId
                 ctx[f"azure.ai.agentserver.user.{key}"] = str(value)
             request_context.set(ctx)
         return user_info