Fix typo in static method binding generator

Co-authored-by: bruvzg <[email protected]>

binding_generator.py

@@ -1152,7 +1152,7 @@ def generate_engine_class_source(class_api, used_classes, fully_used_classes, us
                             method_call += f"return internal::_call_native_mb_ret<{get_gdnative_type(correct_type(return_type, meta_type))}>(___method_bind, _owner"
                     elif is_refcounted(return_type):
                         if method["is_static"]:
-                            method_call += f"return Ref<{return_type}>::___internal_constructor(internal::_call_native_mb_ret_obj<{return_type}>(___method_bind, _nullptr"
+                            method_call += f"return Ref<{return_type}>::___internal_constructor(internal::_call_native_mb_ret_obj<{return_type}>(___method_bind, nullptr"
                         else:
                             method_call += f"return Ref<{return_type}>::___internal_constructor(internal::_call_native_mb_ret_obj<{return_type}>(___method_bind, _owner"
                         is_ref = True