### 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.
set_positional_shadow_atlas_quadrant_subdiv(1, SHADOW_ATLAS_QUADRANT_SUBDIV_4);
	set_positional_shadow_atlas_quadrant_subdiv(2, SHADOW_ATLAS_QUADRANT_SUBDIV_16);
	set_positional_shadow_atlas_quadrant_subdiv(3, SHADOW_ATLAS_QUADRANT_SUBDIV_64);
	set_mesh_lod_threshold(mesh_lod_threshold);
	String id = itos(get_instance_id());
	input_group = "_vp_input" + id;
	gui_input_group = "_vp_gui_input" + id;
	unhandled_input_group = "_vp_unhandled_input" + id;
	shortcut_input_group = "_vp_shortcut_input" + id;
	unhandled_key_input_group = "_vp_unhandled_key_input" + id;
	// Window tooltip.
	gui.tooltip_delay = GLOBAL_DEF(PropertyInfo(Variant::FLOAT, "gui/timers/tooltip_delay_sec", PROPERTY_HINT_RANGE, "0,5,0.01,or_greater"), 0.5);
#ifndef _3D_DISABLED
	set_scaling_3d_mode((Viewport::Scaling3DMode)(int)GLOBAL_GET("rendering/scaling_3d/mode"));
	set_scaling_3d_scale(GLOBAL_GET("rendering/scaling_3d/scale"));
	set_fsr_sharpness((float)GLOBAL_GET("rendering/scaling_3d/fsr_sharpness"));
	set_texture_mipmap_bias((float)GLOBAL_GET("rendering/textures/default_filters/texture_mipmap_bias"));
#endif 
	set_sdf_oversize(sdf_oversize); // Set to server.
}
Viewport::~Viewport() {
	// Erase itself from viewport textures.
	for (ViewportTexture *E : viewport_textures) {
		E->vp = nullptr;
	}
	ERR_FAIL_NULL(RenderingServer::get_singleton());
	RenderingServer::get_singleton()->free(viewport);
}
//
void SubViewport::set_size(const Size2i &p_size) {