### 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.
p_properties->push_back(PropertyInfo(Variant::STRING, "script/source", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL));
}
void GDScript::_bind_methods() {
	ClassDB::bind_vararg_method(METHOD_FLAGS_DEFAULT, "new", &GDScript::_new, MethodInfo("new"));
}
void GDScript::set_path(const String &p_path, bool p_take_over) {
	String old_path = path;
	if (is_root_script()) {
		Script::set_path(p_path, p_take_over);
	}
	this->path = p_path;
	GDScriptCache::move_script(old_path, p_path);
	for (KeyValue<StringName, Ref<GDScript>> &kv : subclasses) {
		kv.value->set_path(p_path, p_take_over);
	}
}
String GDScript::get_script_path() const {
	return path;
}
Error GDScript::load_source_code(const String &p_path) {
	if (p_path.is_empty() || p_path.begins_with("gdscript://") || ResourceLoader::get_resource_type(p_path.get_slice("::", 0)) == "PackedScene") {
		return OK;
	}
	Vector<uint8_t> sourcef;
	Error err;