### 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.
if (reloading) {
		return OK;
	}
	reloading = true;
	bool has_instances;
	{
		MutexLock lock(GDScriptLanguage::singleton->mutex);
		has_instances = instances.size();
	}
	ERR_FAIL_COND_V(!p_keep_state && has_instances, ERR_ALREADY_IN_USE);
	String basedir = path;
	if (basedir.is_empty()) {
		basedir = get_path();
	}
	if (!basedir.is_empty()) {
		basedir = basedir.get_base_dir();
	}
	
#ifdef TOOLS_ENABLED
	if (EditorPaths::get_singleton() && basedir.begins_with(EditorPaths::get_singleton()->get_project_script_templates_dir())) {
		reloading = false;
		return OK;
	}
#endif
	{
		String source_path = path;
		if (source_path.is_empty()) {
			source_path = get_path();
		}