[3.13] GH-121832: Assert that the version number of static builtin types is not changed by PyType_Modified (gh-122290)

Update datetime module and test_type_cache.py to not call PyType_Modified.

(cherry picked from commit e55b05f29ee62cd92b6b9990fd699b78f19432ba, AKA gh--122182)

Co-authored-by: Mark Shannon <mark@hotpy.org>