Constructs a ConfigController object.
\Drupal\Core\Config\StorageInterface $target_storage: The target storage.
\Drupal\Core\Config\StorageInterface $source_storage: The source storage
public function __construct(StorageInterface $target_storage, StorageInterface $source_storage) {
$this->targetStorage = $target_storage;
$this->sourceStorage = $source_storage;
}