Remove unused func parameter of _PyStack_UnpackDict()

Issue #29259.
diff --git a/Objects/abstract.c b/Objects/abstract.c
index ee50f02..682263d 100644
--- a/Objects/abstract.c
+++ b/Objects/abstract.c
@@ -2423,7 +2423,7 @@
 
 int
 _PyStack_UnpackDict(PyObject **args, Py_ssize_t nargs, PyObject *kwargs,
-                    PyObject ***p_stack, PyObject **p_kwnames, PyObject *func)
+                    PyObject ***p_stack, PyObject **p_kwnames)
 {
     PyObject **stack, **kwstack;
     Py_ssize_t nkwargs;