[BUG] fix stop_profile crash

[yizhang2077]

Motivation

current main branch server will crash when call /stop_profile api. It will raise error like this:

await _global_state.tokenizer_manager.stop_profile()
TypeError: object NoneType can’t be used in ‘await’ expression

I think it is introduced in #4741 , which forgot to remove sync stop_profile function, which will cover async version, and engine and http_server have adopt to async stop_profile version.

Modifications

Checklist

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