Issue: MPDF Export PHP < 7.0

    This commit fixes an issue where using MPDF to print Tickets did not work if the PHP version was < 7.0 because MPDF called the random_int function which is only available for PHP 7.0+. Now, we check the PHP version before printing, and if it is less than 7.0, we use the rand function. If it is >= 7.0, we continue to use the random_int function.