### Godot version

v4.0 rc6

### System information

Windows 10

### Issue description

When using a ViewportTexture from a SubViewport on a TextureRect, it throws errors after running the scene once and then switching scenes in the editor.
![Pasted image 20230227212626](https://user-images.githubusercontent.com/44676282/221680047-984fa03e-33d1-4856-9a7f-1700b28423cf.png)


### Steps to reproduce

Run the canvas-scene once.
Switch to another scene in the editor.
Switch back to the canvas-scene

### Minimal reproduction project

[ViewportTextureError.zip](https://github.com/godotengine/godot/files/10844099/ViewportTextureError.zip)

if (resources.size()) {
		ERR_PRINT("Resources still in use at exit (run with --verbose for details).");
		if (OS::get_singleton()->is_stdout_verbose()) {
			for (const KeyValue<String, Resource *> &E : resources) {
				print_line(vformat("Resource still in use: %s (%s)", E.key, E.value->get_class()));
			}
		}
	}
	resources.clear();
}
bool ResourceCache::has(const String &p_path) {
	lock.lock();
	Resource **res = resources.getptr(p_path);
	if (res && (*res)->get_reference_count() == 0) {
		
		(*res)->path_cache = String();
		resources.erase(p_path);
		res = nullptr;
	}
	lock.unlock();
	if (!res) {
		return false;
	}
	return true;
}
Ref<Resource> ResourceCache::get_ref(const String &p_path) {