Simplify sys.breakpointhook implementation (#9519)

Python/sysmodule.c

@@ -151,16 +151,8 @@ sys_breakpointhook(PyObject *self, PyObject *const *args, Py_ssize_t nargs, PyOb
         return NULL;
     }
 
-    PyObject *fromlist = Py_BuildValue("(s)", attrname);
-    if (fromlist == NULL) {
-        Py_DECREF(modulepath);
-        PyMem_RawFree(envar);
-        return NULL;
-    }
-    PyObject *module = PyImport_ImportModuleLevelObject(
-        modulepath, NULL, NULL, fromlist, 0);
+    PyObject *module = PyImport_Import(modulepath);
     Py_DECREF(modulepath);
-    Py_DECREF(fromlist);
 
     if (module == NULL) {
         goto error;