### Godot version

v4.1.1.stable.official [bd6af8e0e]

### System information

Godot v4.1.1.stable - Debian GNU/Linux trixie/sid trixie - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1060 (nvidia) - Intel(R) Core(TM) i5-8400 CPU @ 2.80GHz (6 Threads)

### Issue description

`Area2D`s which extend beyond the bounds of the root viewport, eg. when using a `canvas_items` stretch mode, receive mouse input events even in the black bands letterboxing the game:

https://github.com/godotengine/godot/assets/441188/3beb962f-c1fa-4098-a375-f3d862013577


### Steps to reproduce

1. Set project stretch mode to either `canvas_items` or `viewport`
2. Have an `Area2D` whose `CollisionShape` extends beyond the bounds of the rendered region
3. Connect the `Area2D`'s `mouse_[entered|exited]` signal to something
4. Wave the mouse around in the black areas outside the rendered game

### Minimal reproduction project

Project used for video demo above:

[area2d-oob.zip](https://github.com/godotengine/godot/files/12207031/area2d-oob.zip)

This only demos `mouse_[entered|exited]`, but I first encountered this with the `Area2D.input_event` signal, where it received mouse clicks as well.
ERR_MAIN_THREAD_GUARD;
	if (is_inside_tree() && window_id != DisplayServer::MAIN_WINDOW_ID) {
		ERR_FAIL_MSG("Only the root window can set and use font oversampling.");
	}
	use_font_oversampling = p_oversampling;
	_update_viewport_size();
}
bool Window::is_using_font_oversampling() const {
	ERR_READ_THREAD_GUARD_V(false);
	return use_font_oversampling;
}
DisplayServer::WindowID Window::get_window_id() const {
	ERR_READ_THREAD_GUARD_V(DisplayServer::INVALID_WINDOW_ID);
	if (embedder) {
		return parent->get_window_id();
	}
	return window_id;
}
void Window::set_mouse_passthrough_polygon(const Vector<Vector2> &p_region) {
	ERR_MAIN_THREAD_GUARD;
	mpath = p_region;
	if (window_id == DisplayServer::INVALID_WINDOW_ID) {
		return;
	}
	DisplayServer::get_singleton()->window_set_mouse_passthrough(mpath, window_id);
}
Vector<Vector2> Window::get_mouse_passthrough_polygon() const {
	return mpath;
}
void Window::set_wrap_controls(bool p_enable) {