### 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.
class Font;
class Shortcut;
class StyleBox;
class ThemeOwner;
class Window : public Viewport {
	GDCLASS(Window, Viewport)
public:
	
	enum Mode {
		MODE_WINDOWED = DisplayServer::WINDOW_MODE_WINDOWED,
		MODE_MINIMIZED = DisplayServer::WINDOW_MODE_MINIMIZED,
		MODE_MAXIMIZED = DisplayServer::WINDOW_MODE_MAXIMIZED,
		MODE_FULLSCREEN = DisplayServer::WINDOW_MODE_FULLSCREEN,
		MODE_EXCLUSIVE_FULLSCREEN = DisplayServer::WINDOW_MODE_EXCLUSIVE_FULLSCREEN,
	};
	enum Flags {
		FLAG_RESIZE_DISABLED = DisplayServer::WINDOW_FLAG_RESIZE_DISABLED,
		FLAG_BORDERLESS = DisplayServer::WINDOW_FLAG_BORDERLESS,
		FLAG_ALWAYS_ON_TOP = DisplayServer::WINDOW_FLAG_ALWAYS_ON_TOP,
		FLAG_TRANSPARENT = DisplayServer::WINDOW_FLAG_TRANSPARENT,
		FLAG_NO_FOCUS = DisplayServer::WINDOW_FLAG_NO_FOCUS,
		FLAG_POPUP = DisplayServer::WINDOW_FLAG_POPUP,
		FLAG_EXTEND_TO_TITLE = DisplayServer::WINDOW_FLAG_EXTEND_TO_TITLE,
		FLAG_MOUSE_PASSTHROUGH = DisplayServer::WINDOW_FLAG_MOUSE_PASSTHROUGH,
		FLAG_MAX = DisplayServer::WINDOW_FLAG_MAX,
	};
	enum ContentScaleMode {