FIX: import TypedDict from typing_extensions for python<3.12

[juncgu]

Launching openai serving engine will face the issue:

pydantic.errors.PydanticUserError: Please use typing_extensions.TypedDict instead of typing.TypedDict on Python < 3.12.

For further information visit https://errors.pydantic.dev/2.11/u/typed-dict-version

I am using Python 3.10.16, and it causes the issue above.

FIX #17966

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[DarkLight1337]

Thanks for fixing, however we'll use #17962 as it was opened earlier