mypy

gh-128013: fix data race in `PyUnicode_AsUTF8AndSize` on free-threadi… #11184

Job	Run time
Run mypy on Lib/_pyrepl	22s
Run mypy on Lib/test/libregrtest	22s
Run mypy on Tools/build	25s
Run mypy on Tools/cases_generator	20s
Run mypy on Tools/clinic	24s
Run mypy on Tools/jit	25s
Run mypy on Tools/peg_generator	24s
Run mypy on Tools/wasm	28s
	3m 10s

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