### 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.
_sub_window_update(sw.window);
				} else {
					gui.subwindow_resize_mode = _sub_window_get_resize_margin(sw.window, mb->get_position());
					if (gui.subwindow_resize_mode != SUB_WINDOW_RESIZE_DISABLED) {
						if (gui.subwindow_focused != sw.window) {
							
							_sub_window_grab_focus(sw.window);
						}
						gui.subwindow_resize_from_rect = r;
						gui.subwindow_drag_from = mb->get_position();
						gui.subwindow_drag = SUB_WINDOW_DRAG_RESIZE;
						click_on_window = sw.window;
					}
				}
			}
			if (!click_on_window && r.has_point(mb->get_position())) {
				
				if (gui.subwindow_focused != sw.window) {
					
					_sub_window_grab_focus(sw.window);
				}
				click_on_window = sw.window;
			}
			if (click_on_window) {
				break;
			}
		}
		gui.currently_dragged_subwindow = click_on_window;
		if (!click_on_window && gui.subwindow_focused) {