### 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.
{
		const GDScript *top = this;
		while (top) {
			{
				HashMap<StringName, Variant>::ConstIterator E = top->constants.find(p_name);
				if (E) {
					r_ret = E->value;
					return true;
				}
			}
			{
				HashMap<StringName, Ref<GDScript>>::ConstIterator E = subclasses.find(p_name);
				if (E) {
					r_ret = E->value;
					return true;
				}
			}
			top = top->_base;
		}
		if (p_name == GDScriptLanguage::get_singleton()->strings._script_source) {
			r_ret = get_source_code();
			return true;
		}
	}
	return false;
}
bool GDScript::_set(const StringName &p_name, const Variant &p_value) {