/**
 * Respond to configuration deletion.
 *
 * This may be used when modules need to clean up data that is no longer needed
 * that is related to the configuration being deleted.
 *
 * @param Config $active_config
 *   The configuration object for the settings being deleted.
 */
function hook_config_delete(Config $active_config)
{
    if (strpos($active_config->getName(), 'image.style') === 0) {
        $image_style_name = $active_config->get('name');
        config('mymodule.image_style_addons.' . $image_style_name)->delete();
    }
}