### 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<StringName, Variant> &E : member_default_values_cache) {
		values[E.key] = E.value;
	}
	for (const PropertyInfo &E : members_cache) {
		propnames.push_back(E);
	}
	if (base_cache.is_valid()) {
		base_cache->_update_exports_values(values, propnames);
	}
}
void GDScript::_add_doc(const DocData::ClassDoc &p_inner_class) {
	if (_owner) {
		_owner->_add_doc(p_inner_class);
	} else {
		for (int i = 0; i < docs.size(); i++) {
			if (docs[i].name == p_inner_class.name) {
				docs.remove_at(i);
				break;
			}
		}
		docs.append(p_inner_class);
	}
}
void GDScript::_clear_doc() {