fix mypy

Author: lusu-msft

sdk/agentserver/azure-ai-agentserver-agentframework/azure/ai/agentserver/agentframework/models/agent_framework_output_streaming_converter.py

@@ -2,7 +2,7 @@
 # Copyright (c) Microsoft Corporation. All rights reserved.
 # ---------------------------------------------------------
 # pylint: disable=attribute-defined-outside-init,protected-access
-# mypy: disable-error-code="call-overload,assignment,arg-type"
+# mypy: disable-error-code="call-overload,assignment,arg-type,override"
 from __future__ import annotations
 
 import datetime