### 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_extensions->push_back("gd");
}
bool ResourceFormatLoaderGDScript::handles_type(const String &p_type) const {
	return (p_type == "Script" || p_type == "GDScript");
}
String ResourceFormatLoaderGDScript::get_resource_type(const String &p_path) const {
	String el = p_path.get_extension().to_lower();
	if (el == "gd") {
		return "GDScript";
	}
	return "";
}
void ResourceFormatLoaderGDScript::get_dependencies(const String &p_path, List<String> *p_dependencies, bool p_add_types) {
	Ref<FileAccess> file = FileAccess::open(p_path, FileAccess::READ);
	ERR_FAIL_COND_MSG(file.is_null(), "Cannot open file '" + p_path + "'.");
	String source = file->get_as_utf8_string();
	if (source.is_empty()) {
		return;
	}
	GDScriptParser parser;
	if (OK != parser.parse(source, p_path, false)) {
		return;
	}
	for (const String &E : parser.get_dependencies()) {
		p_dependencies->push_back(E);
	}
}
Error ResourceFormatSaverGDScript::save(const Ref<Resource> &p_resource, const String &p_path, uint32_t p_flags) {