### 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
int line = scr->get_member_line(p_symbol);
					if (line >= 0) {
						r_result.type = ScriptLanguage::LOOKUP_RESULT_SCRIPT_LOCATION;
						r_result.location = line;
						r_result.script = scr;
						return OK;
					}
					Ref<Script> base_script = scr->get_base_script();
					if (base_script.is_valid()) {
						base_type.script_type = base_script;
					} else {
						base_type.kind = GDScriptParser::DataType::NATIVE;
						base_type.builtin_type = Variant::OBJECT;
						base_type.native_type = scr->get_instance_base_type();
					}
				} else {
					base_type.kind = GDScriptParser::DataType::UNRESOLVED;
				}
			} 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;
				}
				if (ClassDB::has_method(class_name, p_symbol, true)) {
					r_result.type = ScriptLanguage::LOOKUP_RESULT_CLASS_METHOD;
					r_result.class_name = base_type.native_type;
					r_result.class_member = p_symbol;
					return OK;