### 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.
script_list(this) {
	{
		MutexLock lock(GDScriptLanguage::get_singleton()->mutex);
		GDScriptLanguage::get_singleton()->script_list.add(&script_list);
	}
	path = vformat("gdscript://%d.gd", get_instance_id());
}
void GDScript::_save_orphaned_subclasses(GDScript::ClearData *p_clear_data) {
	struct ClassRefWithName {
		ObjectID id;
		String fully_qualified_name;
	};
	Vector<ClassRefWithName> weak_subclasses;
	
	for (KeyValue<StringName, Ref<GDScript>> &E : subclasses) {
		E.value->_owner = nullptr; 
		ClassRefWithName subclass;
		subclass.id = E.value->get_instance_id();
		subclass.fully_qualified_name = E.value->fully_qualified_name;
		weak_subclasses.push_back(subclass);
	}
	
	for (KeyValue<StringName, Ref<GDScript>> &E : subclasses) {
		p_clear_data->scripts.insert(E.value);
	}
	subclasses.clear();
	
	for (KeyValue<StringName, Variant> &E : constants) {
		GDScript *gdscr = _get_gdscript_from_variant(E.value);
		if (gdscr != nullptr) {