chore: handle tuple-like cancellation errors

What does this merge request do and why?

Langgraph cleanup sometimes returns a tuple in the exception object: https://cloudlogging.app.goo.gl/QYdnTtPDP9HYvSwP7, we need to handle it properly as well. Let's use in method that checks inclusion:

• When ('AIO_CANCEL_STOP_WORKFLOW_REQUEST', <Task cancelled name='Task-275689' coro=<AsyncExitStack.__aexit__() done, defined at /usr/local/lib/python3.12/contextlib.py:707>>) is a tuple
• When AIO_CANCEL_STOP_WORKFLOW_REQUEST is a string