### 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(0);
	return theme_owner->get_theme_default_base_scale();
}
Ref<Font> Window::get_theme_default_font() const {
	ERR_READ_THREAD_GUARD_V(Ref<Font>());
	return theme_owner->get_theme_default_font();
}
int Window::get_theme_default_font_size() const {
	ERR_READ_THREAD_GUARD_V(0);
	return theme_owner->get_theme_default_font_size();
}
void Window::begin_bulk_theme_override() {
	ERR_MAIN_THREAD_GUARD;
	bulk_theme_override = true;
}
void Window::end_bulk_theme_override() {
	ERR_MAIN_THREAD_GUARD;
	ERR_FAIL_COND(!bulk_theme_override);
	bulk_theme_override = false;
	_notify_theme_override_changed();
}
Rect2i Window::get_parent_rect() const {
	ERR_READ_THREAD_GUARD_V(Rect2i());
	ERR_FAIL_COND_V(!is_inside_tree(), Rect2i());
	if (is_embedded()) {