### 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 (world_3d == p_world_3d) {
		return;
	}
	if (is_inside_tree()) {
		_propagate_exit_world_3d(this);
	}
	if (own_world_3d.is_valid() && world_3d.is_valid()) {
		world_3d->disconnect_changed(callable_mp(this, &Viewport::_own_world_3d_changed));
	}
	world_3d = p_world_3d;
	if (own_world_3d.is_valid()) {
		if (world_3d.is_valid()) {
			own_world_3d = world_3d->duplicate();
			world_3d->connect_changed(callable_mp(this, &Viewport::_own_world_3d_changed));
		} else {
			own_world_3d = Ref<World3D>(memnew(World3D));
		}
	}
	if (is_inside_tree()) {
		_propagate_enter_world_3d(this);
	}
	if (is_inside_tree()) {
		RenderingServer::get_singleton()->viewport_set_scenario(viewport, find_world_3d()->get_scenario());
	}
	_update_audio_listener_3d();
}
void Viewport::_own_world_3d_changed() {