### Godot version

4.1.1

### System information

windows 11

### Issue description

When registering a type with class_name and using that class name to declare a variable in code only, autocomplete works as expected anywhere in other nodes/scenes. However, if making a custom scene node that extends a script with the class_name, if that custom scene is instantiated in a different scene, even if the type is specified, it only shows the parent node's functions and not any of the extended functionality. I have made a basic project showing the issue

### Steps to reproduce

I have made a very simple project showing the issue. https://github.com/mmmmmmmmmmmmmmmmmmmdonuts/godot_4_autocomplete_issue essentially, the extended Node scene will only show the custom function when both the type is specified as well as the type afterwards following "as" 
e.g. `@onready var my_class_4: MyClass = $MyClass4 as MyClass`

### Minimal reproduction project

https://github.com/mmmmmmmmmmmmmmmmmmmdonuts/godot_4_autocomplete_issue
base_type.native_type = scr->get_instance_base_type();
					}
				} else {
					return false;
				}
			} break;
			case GDScriptParser::DataType::NATIVE: {
				if (!ClassDB::class_exists(base_type.native_type)) {
					return false;
				}
				MethodBind *mb = ClassDB::get_method(base_type.native_type, p_method);
				if (mb) {
					r_type = _type_from_property(mb->get_return_info());
					return true;
				}
				return false;
			} break;
			case GDScriptParser::DataType::BUILTIN: {
				Callable::CallError err;
				Variant tmp;
				Variant::construct(base_type.builtin_type, tmp, nullptr, 0, err);
				if (err.error != Callable::CallError::CALL_OK) {
					return false;
				}
				List<MethodInfo> methods;
				tmp.get_method_list(&methods);
				for (const MethodInfo &mi : methods) {
					if (mi.name == p_method) {
						r_type = _type_from_property(mi.return_val);
						return true;