### 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
} break;
			case GDScriptParser::DataType::NATIVE: {
				StringName class_name = base_type.native_type;
				if (!ClassDB::class_exists(class_name)) {
					base_type.kind = GDScriptParser::DataType::UNRESOLVED;
					break;
				}
				MethodInfo info;
				int method_args = 0;
				if (ClassDB::get_method_info(class_name, p_method, &info)) {
					method_args = info.arguments.size();
					if (base.get_type() == Variant::OBJECT) {
						Object *obj = base.operator Object *();
						if (obj) {
							List<String> options;
							obj->get_argument_options(p_method, p_argidx, &options);
							for (String &opt : options) {
								if (opt.is_quoted()) {
									opt = opt.unquote().quote(quote_style); 
								}
								ScriptLanguage::CodeCompletionOption option(opt, ScriptLanguage::CODE_COMPLETION_KIND_FUNCTION);
								r_result.insert(option.display, option);
							}
						}
					}
					if (p_argidx < method_args) {
						PropertyInfo arg_info = info.arguments[p_argidx];
						if (arg_info.usage & (PROPERTY_USAGE_CLASS_IS_ENUM | PROPERTY_USAGE_CLASS_IS_BITFIELD)) {
							_find_enumeration_candidates(p_context, arg_info.class_name, r_result);
						}