### 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 (!is_enum && doc_enums.has("@unnamed_enums")) {
			for (int i = 0; i < doc_enums["@unnamed_enums"].values.size(); i++) {
				if (E.key == doc_enums["@unnamed_enums"].values[i].name) {
					is_enum = true;
					DocData::ConstantDoc constant_doc;
					constant_doc.enumeration = "@unnamed_enums";
					DocData::constant_doc_from_variant(constant_doc, E.key, E.value, doc_enums["@unnamed_enums"].values[i].description);
					doc.constants.push_back(constant_doc);
					break;
				}
			}
		}
		if (!is_enum) {
			DocData::ConstantDoc constant_doc;
			String const_description;
			if (doc_constants.has(E.key)) {
				const_description = doc_constants[E.key];
			}
			DocData::constant_doc_from_variant(constant_doc, E.key, E.value, const_description);
			doc.constants.push_back(constant_doc);
		}
	}
	for (KeyValue<StringName, Ref<GDScript>> &E : subclasses) {
		E.value->_update_doc();
	}
	_add_doc(doc);
}
#endif
bool GDScript::_update_exports(bool *r_err, bool p_recursive_call, PlaceHolderScriptInstance *p_instance_to_update) {