Php Form Builder - Bootstrap 4 Modal Contact Form

<?php
use phpformbuilder\Form;
use phpformbuilder\Validator\Validator;

/* =============================================
    start session and include form class
============================================= */

session_start();
include_once rtrim($_SERVER['DOCUMENT_ROOT'], DIRECTORY_SEPARATOR) . '/phpformbuilder/Form.php';

/* =============================================
    validation if posted
============================================= */

if ($_SERVER["REQUEST_METHOD"] == "POST" && Form::testToken('contact-form-1-modal') === true) {
    // create validator & auto-validate required fields
    $validator = Form::validate('contact-form-1-modal');

    // additional validation
    $validator->maxLength(100)->validate('message');
    $validator->email()->validate('user-email');

    // recaptcha validation
    $validator->recaptcha('6LeNWaQUAAAAAOnei_86FAp7aRZCOhNwK3e2o2x2', 'Recaptcha Error')->validate('g-recaptcha-response');

    // check for errors
    if ($validator->hasErrors()) {
        $_SESSION['errors']['contact-form-1-modal'] = $validator->getAllErrors();
    } else {
        $_POST['message'] = nl2br($_POST['message']);
        $email_config = array(
            'sender_email'    => 'contact@phpformbuilder.pro',
            'sender_name'     => 'Php Form Builder',
            'recipient_email' => addslashes($_POST['user-email']),
            'subject'         => 'Contact from Php Form Builder',
            'filter_values'   => 'contact-form-1-modal',
            'sent_message'    => '<p class="card-panel teal accent-2">Your message has been successfully sent !</p>'
        );
        $sent_message = Form::sendMail($email_config);
        Form::clear('contact-form-1-modal');
    }
}

/* ==================================================
    The Form
================================================== */

$form = new Form('contact-form-1-modal', 'horizontal', 'novalidate', 'material');
// $form->setMode('development');
$form->startFieldset('Please fill in this form to contact us');
$form->addHtml('<p class="text-warning">All fields are required</p>');
$form->groupInputs('user-name', 'user-first-name');
$form->setCols(0, 6, 'xs');
$form->addIcon('user-name', '<i class="material-icons" aria-hidden="true">person</i>', 'before');
$form->addInput('text', 'user-name', '', '', 'placeholder=Name, required');
$form->addIcon('user-first-name', '<i class="material-icons" aria-hidden="true">person</i>', 'before');
$form->addInput('text', 'user-first-name', '', '', 'placeholder=First Name, required');
$form->setCols(0, 12, 'xs');
$form->addIcon('user-email', '<i class="material-icons" aria-hidden="true">mail_outline</i>', 'before');
$form->addInput('email', 'user-email', '', '', 'placeholder=Email, required');
$form->addIcon('user-phone', '<i class="material-icons" aria-hidden="true">phone</i>', 'before');
$form->addInput('tel', 'user-phone', '', '', 'data-intphone=true, data-fv-intphonenumber=true, required');
$form->addTextarea('message', '', '', 'cols=30, rows=4, placeholder=Message, required');
$form->setCols(6, 6, 'xs');
$form->addCheckbox('newsletter', '', '1', 'class=lcswitch, data-ontext=Yes, data-offtext=No, data-theme=yellow, checked');
$form->printCheckboxGroup('newsletter', 'Suscribe to Newsletter');
$form->setCols(0, 12, 'xs');
$form->addRecaptchaV3('6LeNWaQUAAAAAGO_c1ORq2wla-PEFlJruMzyH5L6', 'material-contact-form-1-modal');
$form->centerButtons(true);
$form->addBtn('button', 'reset-btn', 1, 'Cancel <i class="material-icons right">cancel</i>', 'class=btn orange darken-1 waves-effect waves-light, data-modal-close=modal-target', 'my-btn-group');
$form->addBtn('submit', 'submit-btn', 1, 'Send <i class="material-icons right">done</i>', 'class=btn waves-effect waves-light ladda-button, data-style=zoom-in', 'my-btn-group');
$form->printBtnGroup('my-btn-group');
$form->endFieldset();

// word-character-count plugin
$form->addPlugin('word-character-count', '#message', 'default', array('%maxAuthorized%' => 100));

// modal
$form->modal('#modal-target');

// jQuery validation
$form->addPlugin('formvalidation', '#contact-form-1-modal');
?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <title>Material Design Modal Contact Form - How to create PHP forms easily</title>
    <meta name="description" content="Material Design Form Generator - how to create a Modal Contact Form with Php Form Builder Class">
    <link rel="canonical" href="https://www.phpformbuilder.pro/templates/material-forms/contact-form-1-modal.php" />

    <!-- Materialize CSS -->

    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/css/materialize.min.css">

    <!-- Material icons CSS -->

    <link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
    <?php $form->printIncludes('css'); ?>
</head>
<body>
    <h1 class="center-align">Php Form Builder - Bootstrap 4 Modal Contact Form</h1>
    <div class="container">
        <?php
            // information for users - remove this in your forms
            include_once '../assets/material-forms-notice.php';
        ?>

        <div class="row">
            <div class="col m11 l10">
                <?php
                if (isset($sent_message)) {
                    echo $sent_message;
                }
                ?>
                <a data-remodal-target="modal-target" class="waves-effect waves-light btn-large">Contact Us</a>
                <?php
                $form->render();
                ?>
            </div>
        </div>
    </div>

    <!-- jQuery -->

    <script src="https://code.jquery.com/jquery-3.2.1.min.js" integrity="sha256-hwg4gsxgFZhOsEEamdOYGBf13FyQuiTwlAQgxVSNgt4=" crossorigin="anonymous"></script>

    <!-- Materialize JavaScript -->

    <script src="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/js/materialize.min.js"></script>

    <?php
        $form->printIncludes('js');
        $form->printJsCode();
    ?>
</body>
</html>