gh-105927: finalize_modules_clear_weaklist() uses _PyWeakref_GET_REF() (#105971)

finalize_modules_clear_weaklist() now holds a strong reference to the
module longer than before: replace PyWeakref_GET_OBJECT() with
_PyWeakref_GET_REF().

Objects/moduleobject.c

@@ -504,7 +504,7 @@ PyModule_GetDict(PyObject *m)
         PyErr_BadInternalCall();
         return NULL;
     }
-    return _PyModule_GetDict(m);
+    return _PyModule_GetDict(m);  // borrowed reference
 }
 
 PyObject*