### 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;
	Ref<Theme> default_theme = ThemeDB::get_singleton()->get_default_theme();
	p_list->push_back(PropertyInfo(Variant::NIL, GNAME("Theme Overrides", "theme_override_"), PROPERTY_HINT_NONE, "theme_override_", PROPERTY_USAGE_GROUP));
	{
		List<StringName> names;
		default_theme->get_color_list(get_class_name(), &names);
		for (const StringName &E : names) {
			uint32_t usage = PROPERTY_USAGE_EDITOR | PROPERTY_USAGE_CHECKABLE;
			if (theme_color_override.has(E)) {
				usage |= PROPERTY_USAGE_STORAGE | PROPERTY_USAGE_CHECKED;
			}