### 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.
ERR_FAIL_COND(p_source == nullptr);
	if (is_ignoring_warnings) {
		return;
	}
	if (GLOBAL_GET("debug/gdscript/warnings/exclude_addons").booleanize() && script_path.begins_with("res://addons/")) {
		return;
	}
	if (ignored_warnings.has(p_code)) {
		return;
	}
	int warn_level = (int)GLOBAL_GET(GDScriptWarning::get_settings_path_from_code(p_code));
	if (!warn_level) {
		return;
	}
	GDScriptWarning warning;
	warning.code = p_code;
	warning.symbols = p_symbols;
	warning.start_line = p_source->start_line;
	warning.end_line = p_source->end_line;
	warning.leftmost_column = p_source->leftmost_column;
	warning.rightmost_column = p_source->rightmost_column;
	if (warn_level == GDScriptWarning::WarnLevel::ERROR || bool(GLOBAL_GET("debug/gdscript/warnings/treat_warnings_as_errors"))) {
		push_error(warning.get_message() + String(" (Warning treated as error.)"), p_source);
		return;
	}
	List<GDScriptWarning>::Element *before = nullptr;
	for (List<GDScriptWarning>::Element *E = warnings.front(); E; E = E->next()) {