### Godot version

4.0-rc1

### System information

Windows 10

### Issue description

The code: `@export @onready var camera_system : Node3D`

Is throwing: `Line 5:The "@onready" annotation will make the default value to be set after the "@export" takes effect and will override it. (Warning treated as error.)` and is crashing the game.

Unchecking "Treat Warning as Errors" seems to have no effect:

![imagen](https://user-images.githubusercontent.com/248383/217900756-8e214c40-68fb-4fb2-8509-a1e689725930.png)

![imagen](https://user-images.githubusercontent.com/248383/217901253-3b758ebc-48e9-40fe-8d77-16fce7cbae88.png)


### Steps to reproduce

- Write `@export @onready var some_var : Node3D`
- In Project Settings, uncheck `Treat Warning as Errors`
- Try to run the project, a `Parser Error` will be thrown.

### Minimal reproduction project

It's as simple as adding one line of code, so I'm not sure a MRP is needed.
for (const KeyValue<String, DocData::EnumDoc> &E : doc_enums) {
		if (!E.value.description.is_empty()) {
			doc.enums[E.key] = E.value.description;
		}
	}
	List<MethodInfo> methods;
	_get_script_method_list(&methods, false);
	for (int i = 0; i < methods.size(); i++) {
		
		if (methods[i].name[0] == '@') {
			continue;
		}
		DocData::MethodDoc method_doc;
		const String &class_name = methods[i].name;
		if (member_functions.has(class_name)) {
			GDScriptFunction *fn = member_functions[class_name];
			
			GDScriptDataType return_type = fn->get_return_type();
			if (return_type.kind == GDScriptDataType::GDSCRIPT) {
				methods[i].return_val.class_name = _get_gdscript_reference_class_name(Object::cast_to<GDScript>(return_type.script_type));
			}
			
			for (int j = 0; j < fn->get_argument_count(); j++) {
				GDScriptDataType arg_type = fn->get_argument_type(j);
				if (arg_type.kind == GDScriptDataType::GDSCRIPT) {
					methods[i].arguments[j].class_name = _get_gdscript_reference_class_name(Object::cast_to<GDScript>(arg_type.script_type));
				}
			}
		}
		if (doc_functions.has(methods[i].name)) {