Add validation constraints

[DieterHolvoet]

Summary

Add Symfony validation constraints.

Basic example

e.g. for when we're using custom request classes

<?php

namespace Drupal\module\Request;

use Drupal\wmrecaptcha\Plugin\Validation\Constraint as ReCaptcha;
use Symfony\Component\Validator\Constraints as Assert;

class SubmitApiRequest
{
    /**
     * @Assert\NotBlank
     * @ReCaptcha\Trusted
     */
    public string $reCaptchaToken;
}