### Godot version

v4.0.beta.custom_build [0a9e6e478]

### System information

Ubuntu, Nvidia, Vulkan

### Issue description

When a Camera2D is freed - either explicitly or by being a child of a scene that is being switched away from via a method like `get_tree().change_scene_to_file()` - then this camera somehow stays active instead of Godot properly switching to no-camera-mode.

`get_viewport().get_camera_2d()` then returns all sorts of funny things from `<Freed Object>`  (it's supposed to return `null`) to arbitrary nodes of the current scene (not cameras).

This can lead to crashes.

### Steps to reproduce

checkout the MRP.

note that the "Go to scene 2" button switches places after pressing it.
that is because a camera is still active that does not exist in the current tree.

restart it a couple of times and spam the "Go to scene 2" button.
notice the garbage output.

### Minimal reproduction project

[godot_4_camera_bug.zip](https://github.com/godotengine/godot/files/10560455/godot_4_camera_bug.zip)
return default_canvas_item_texture_repeat;
}
void Viewport::set_vrs_mode(Viewport::VRSMode p_vrs_mode) {
	
	vrs_mode = p_vrs_mode;
	switch (p_vrs_mode) {
		case VRS_TEXTURE: {
			RS::get_singleton()->viewport_set_vrs_mode(viewport, RS::VIEWPORT_VRS_TEXTURE);
		} break;
		case VRS_XR: {
			RS::get_singleton()->viewport_set_vrs_mode(viewport, RS::VIEWPORT_VRS_XR);
		} break;
		default: {
			RS::get_singleton()->viewport_set_vrs_mode(viewport, RS::VIEWPORT_VRS_DISABLED);
		} break;
	}
	notify_property_list_changed();
}
Viewport::VRSMode Viewport::get_vrs_mode() const {