Fix query to fetch secrets given a list of users

namespace OCA\EcloudAccounts\Db;

use OCA\TwoFactorTOTP\Service\ITotp;

use OCP\DB\QueryBuilder\IQueryBuilder;

use OCP\IDBConnection;

class TwoFactorMapper {

		if (!empty($usernames)) {

			$qb->andWhere('user_id IN (:usernames)')

				->setParameter('usernames', implode(',', $usernames));

				->setParameter('usernames', $usernames, IQueryBuilder::PARAM_STR_ARRAY);

		}

		$result = $qb->execute();