### 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.
return false;
	}
	Transform2D window_ofs;
	window_ofs.set_origin(-gui.subwindow_focused->get_position());
	Ref<InputEvent> ev = p_event->xformed_by(window_ofs);
	gui.subwindow_focused->_window_input(ev);
	return true;
}
void Viewport::_update_mouse_over() {
	
	
	if (is_attached_in_viewport()) {
		
		return;
	}
	if (get_tree()->get_root()->is_embedding_subwindows() || is_sub_viewport()) {
		
		_update_mouse_over(gui.last_mouse_pos);
	} else {
		
		Window *receiving_window = get_tree()->get_root()->gui.windowmanager_window_over;
		if (!receiving_window) {
			return;
		}
		Vector2 pos = DisplayServer::get_singleton()->mouse_get_position() - receiving_window->get_position();
		pos = receiving_window->get_final_transform().affine_inverse().xform(pos);
		receiving_window->_update_mouse_over(pos);
	}
}
void Viewport::_update_mouse_over(Vector2 p_pos) {