### 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.
return script;
}
ScriptLanguage *GDScriptInstance::get_language() {
	return GDScriptLanguage::get_singleton();
}
const Variant GDScriptInstance::get_rpc_config() const {
	return script->get_rpc_config();
}
void GDScriptInstance::reload_members() {
#ifdef DEBUG_ENABLED
	Vector<Variant> new_members;
	new_members.resize(script->member_indices.size());
	
	for (KeyValue<StringName, GDScript::MemberInfo> &E : script->member_indices) {
		if (member_indices_cache.has(E.key)) {
			Variant value = members[member_indices_cache[E.key]];
			new_members.write[E.value.index] = value;
		}
	}
	members.resize(new_members.size()); 
	
	members = new_members;
	
	member_indices_cache.clear();
	for (const KeyValue<StringName, GDScript::MemberInfo> &E : script->member_indices) {
		member_indices_cache[E.key] = E.value.index;
	}
#endif
}
GDScriptInstance::GDScriptInstance() {