### 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.
_super_implicit_constructor(this, instance, r_error);
	if (r_error.error != Callable::CallError::CALL_OK) {
		instance->script = Ref<GDScript>();
		instance->owner->set_script_instance(nullptr);
		{
			MutexLock lock(GDScriptLanguage::singleton->mutex);
			instances.erase(p_owner);
		}
		ERR_FAIL_V_MSG(nullptr, "Error constructing a GDScriptInstance.");
	}
	if (p_argcount < 0) {
		return instance;
	}
	initializer = _super_constructor(this);
	if (initializer != nullptr) {
		initializer->call(instance, p_args, p_argcount, r_error);
		if (r_error.error != Callable::CallError::CALL_OK) {
			instance->script = Ref<GDScript>();
			instance->owner->set_script_instance(nullptr);
			{
				MutexLock lock(GDScriptLanguage::singleton->mutex);
				instances.erase(p_owner);
			}
			ERR_FAIL_V_MSG(nullptr, "Error constructing a GDScriptInstance.");
		}
	}
	
	return instance;
}
Variant GDScript::_new(const Variant **p_args, int p_argcount, Callable::CallError &r_error) {