### 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 *sl = sptr;
			while (sl) {
				HashMap<StringName, Vector<StringName>>::ConstIterator E = sl->_signals.find(p_name);
				if (E) {
					r_ret = Signal(this->owner, E->key);
					return true; 
				}
				sl = sl->_base;
			}
		}
		{
			
			const GDScript *sl = sptr;
			while (sl) {
				HashMap<StringName, GDScriptFunction *>::ConstIterator E = sl->member_functions.find(p_name);
				if (E) {
					if (sptr->rpc_config.has(p_name)) {
						r_ret = Callable(memnew(GDScriptRPCCallable(this->owner, E->key)));
					} else {
						r_ret = Callable(this->owner, E->key);
					}
					return true; 
				}
				sl = sl->_base;
			}
		}
		{
			HashMap<StringName, GDScriptFunction *>::ConstIterator E = sptr->member_functions.find(GDScriptLanguage::get_singleton()->strings._get);
			if (E) {
				Variant name = p_name;