Test

Make various `email.Policy` use sites generic over the message type #29324

Job	Run time
Run pytype against the stubs	1m 56s
Test typeshed with pyright (Linux, 3.9)	1m 0s
Run mypy against the stubs (linux, 3.9)	2m 5s
Test typeshed with pyright (Linux, 3.10)	1m 0s
Run mypy against the stubs (linux, 3.10)	1m 59s
Test typeshed with pyright (Linux, 3.11)	56s
Run mypy on the test cases	3m 36s
Run mypy against the stubs (linux, 3.11)	1m 55s
Test typeshed with pyright (Linux, 3.12)	57s
Run mypy against the stubs (linux, 3.12)	2m 3s
Test typeshed with pyright (Linux, 3.13)	56s
Run the stub_uploader tests	4m 15s
Run mypy against the stubs (linux, 3.13)	2m 6s
Test typeshed with pyright (Windows, 3.9)	1m 2s
Run mypy against the stubs (win32, 3.9)	1m 59s
Test typeshed with pyright (Windows, 3.10)	56s
Check typeshed structure	11s
Run mypy against the stubs (win32, 3.10)	2m 1s
Test typeshed with pyright (Windows, 3.11)	59s
Run mypy against the stubs (win32, 3.11)	1m 54s
Test typeshed with pyright (Windows, 3.12)	1m 1s
Run mypy against the stubs (win32, 3.12)	2m 10s
Test typeshed with pyright (Windows, 3.13)	1m 2s
Run mypy against the stubs (win32, 3.13)	2m 8s
Test typeshed with pyright (Darwin, 3.9)	55s
Test typeshed with pyright (Darwin, 3.10)	57s
Test typeshed with pyright (Darwin, 3.11)	55s
Run mypy against the stubs (darwin, 3.9)	1m 56s
Test typeshed with pyright (Darwin, 3.12)	56s
Run mypy against the stubs (darwin, 3.10)	1m 57s
Test typeshed with pyright (Darwin, 3.13)	1m 4s
Run mypy against the stubs (darwin, 3.11)	1m 57s
Run mypy against the stubs (darwin, 3.12)	2m 7s
Run mypy against the stubs (darwin, 3.13)	2m 4s
	54m 55s

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