Extracts the configuration entity ID from the full configuration name.
string $config_name: The full configuration name to extract the ID from. E.g. 'views.view.archive'.
string $config_prefix: The config prefix of the configuration entity. E.g. 'views.view'
string The ID of the configuration entity.
public static function getIDFromConfigName($config_name, $config_prefix) {
return substr($config_name, strlen($config_prefix . '.'));
}