bugfix: Keep registered types until after Py_Finalize(). Fix #4459 (#4486)

* Keep registered types until after Py_Finalize(). Fix #4459

* Address reviewer comments

Author: Skylion007

include/pybind11/embed.h

@@ -254,13 +254,16 @@ inline void finalize_interpreter() {
     if (builtins.contains(id) && isinstance<capsule>(builtins[id])) {
         internals_ptr_ptr = capsule(builtins[id]);
     }
+
+    Py_Finalize();
+
     // Local internals contains data managed by the current interpreter, so we must clear them to
     // avoid undefined behaviors when initializing another interpreter
+    // Must be cleared only after Py_Finalize() so atexit and other hooks can still use
+    // registered_types
     detail::get_local_internals().registered_types_cpp.clear();
     detail::get_local_internals().registered_exception_translators.clear();
 
-    Py_Finalize();
-
     if (internals_ptr_ptr) {
         delete *internals_ptr_ptr;
         *internals_ptr_ptr = nullptr;