### 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.
bool is_size_2d_override_stretch_enabled() const override;
	void set_update_mode(UpdateMode p_mode);
	UpdateMode get_update_mode() const;
	void set_clear_mode(ClearMode p_mode);
	ClearMode get_clear_mode() const;
	virtual Transform2D get_screen_transform_internal(bool p_absolute_position = false) const override;
	virtual Transform2D get_popup_base_transform() const override;
	virtual bool is_directly_attached_to_screen() const override;
	virtual bool is_attached_in_viewport() const override;
	virtual bool is_sub_viewport() const override { return true; };
	void _validate_property(PropertyInfo &p_property) const;
	SubViewport();
	~SubViewport();
};
VARIANT_ENUM_CAST(Viewport::Scaling3DMode);
VARIANT_ENUM_CAST(SubViewport::UpdateMode);
VARIANT_ENUM_CAST(Viewport::PositionalShadowAtlasQuadrantSubdiv);
VARIANT_ENUM_CAST(Viewport::MSAA);
VARIANT_ENUM_CAST(Viewport::ScreenSpaceAA);
VARIANT_ENUM_CAST(Viewport::DebugDraw);
VARIANT_ENUM_CAST(Viewport::SDFScale);
VARIANT_ENUM_CAST(Viewport::SDFOversize);
VARIANT_ENUM_CAST(Viewport::VRSMode);
VARIANT_ENUM_CAST(SubViewport::ClearMode);
VARIANT_ENUM_CAST(Viewport::RenderInfo);
VARIANT_ENUM_CAST(Viewport::RenderInfoType);
VARIANT_ENUM_CAST(Viewport::DefaultCanvasItemTextureFilter);
VARIANT_ENUM_CAST(Viewport::DefaultCanvasItemTextureRepeat);
#endif