mypy

gh-143012: use `Py_ssize_t` cast for `PyBytes_FromStringAndSize` (#14… #18686

Job	Run time
Run mypy on Tools/clinic	19s
Run mypy on Tools/cases_generator	18s
Run mypy on Lib/_pyrepl	20s
Run mypy on Tools/check-c-api-docs	18s
Run mypy on Lib/tomllib	21s
Run mypy on Tools/build	19s
Run mypy on Tools/peg_generator	20s
Run mypy on Lib/test/libregrtest	22s
Run mypy on Tools/jit	20s
	2m 57s

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