[3.13] gh-120782: Update internal type cache when reloading datetime (GH-120829)...

[3.13] gh-120782: Update internal type cache when reloading datetime (GH-120829) (#120855)

* [3.13] gh-120782: Update internal type cache when reloading datetime

When reloading _datetime module, the single-phase version did not invoke the PyInit__datetime function, whereas the current multi-phase version updates the static types through the module init. The outdated static type cache in the interpreter state needs to be invalidated at the end of reloading the multi-phase module.