mypy

gh-146244: Fix initconfig.c SET_ITEM macro leaks dict on expression f… #20169

Job	Run time
Run mypy on Lib/test/libregrtest	18s
Run mypy on Lib/_pyrepl	19s
Run mypy on Tools/check-c-api-docs	20s
Run mypy on Tools/build	21s
Run mypy on Lib/tomllib	16s
Run mypy on Tools/cases_generator	19s
Run mypy on Tools/clinic	18s
Run mypy on Tools/jit	18s
Run mypy on Tools/peg_generator	20s
	2m 49s

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