### 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)
handle_input_locally = p_enable;
}
bool Viewport::is_handling_input_locally() const {
	return handle_input_locally;
}
void Viewport::set_default_canvas_item_texture_filter(DefaultCanvasItemTextureFilter p_filter) {
	ERR_FAIL_INDEX(p_filter, DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_MAX);
	if (default_canvas_item_texture_filter == p_filter) {
		return;
	}
	default_canvas_item_texture_filter = p_filter;
	switch (default_canvas_item_texture_filter) {
		case DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_NEAREST:
			RS::get_singleton()->viewport_set_default_canvas_item_texture_filter(viewport, RS::CANVAS_ITEM_TEXTURE_FILTER_NEAREST);
			break;
		case DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_LINEAR:
			RS::get_singleton()->viewport_set_default_canvas_item_texture_filter(viewport, RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR);
			break;
		case DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_LINEAR_WITH_MIPMAPS:
			RS::get_singleton()->viewport_set_default_canvas_item_texture_filter(viewport, RS::CANVAS_ITEM_TEXTURE_FILTER_LINEAR_WITH_MIPMAPS);
			break;
		case DEFAULT_CANVAS_ITEM_TEXTURE_FILTER_NEAREST_WITH_MIPMAPS:
			RS::get_singleton()->viewport_set_default_canvas_item_texture_filter(viewport, RS::CANVAS_ITEM_TEXTURE_FILTER_NEAREST_WITH_MIPMAPS);
			break;
		default: {
		}
	}
}
Viewport::DefaultCanvasItemTextureFilter Viewport::get_default_canvas_item_texture_filter() const {