### 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_READ_THREAD_GUARD_V(false);
	return theme_owner->has_owner_node();
}
void Window::set_theme(const Ref<Theme> &p_theme) {
	ERR_MAIN_THREAD_GUARD;
	if (theme == p_theme) {
		return;
	}
	if (theme.is_valid()) {
		theme->disconnect_changed(callable_mp(this, &Window::_theme_changed));
	}
	theme = p_theme;
	if (theme.is_valid()) {
		theme_owner->propagate_theme_changed(this, this, is_inside_tree(), true);
		theme->connect_changed(callable_mp(this, &Window::_theme_changed), CONNECT_DEFERRED);
		return;
	}
	Control *parent_c = Object::cast_to<Control>(get_parent());
	if (parent_c && parent_c->has_theme_owner_node()) {
		theme_owner->propagate_theme_changed(this, parent_c->get_theme_owner_node(), is_inside_tree(), true);
		return;
	}
	Window *parent_w = cast_to<Window>(get_parent());
	if (parent_w && parent_w->has_theme_owner_node()) {
		theme_owner->propagate_theme_changed(this, parent_w->get_theme_owner_node(), is_inside_tree(), true);
		return;
	}
	theme_owner->propagate_theme_changed(this, nullptr, is_inside_tree(), true);
}
Ref<Theme> Window::get_theme() const {