Move the logic to check if dest users are required to a dedicated constraint

- Create a dedicated constraint to check if the destUsers are required by the applied transition.
- Apply on WorkflowTransitionContextDTO and, if required, use the built-in constraints
- create tests

src/Bundle/ChillMainBundle/Workflow/Validator/TransitionHasDestUserIfRequired.php

@@ -0,0 +1,31 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * Chill is a software for social workers
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace Chill\MainBundle\Workflow\Validator;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * Check that the next stop has a dest user if this is required by the transition.
+ */
+#[\Attribute]
+class TransitionHasDestUserIfRequired extends Constraint
+{
+    public $messageDestUserRequired = 'workflow.You must add at least one dest user or email';
+    public $codeDestUserRequired = '637c20a6-822c-11ef-a4dd-07b4c0c0efa8';
+    public $messageDestUserNotAuthorized = 'workflow.dest_user_not_authorized';
+    public $codeDestUserNotAuthorized = '8377be2c-822e-11ef-b53a-57ad65828a8e';
+
+    public function getTargets(): string
+    {
+        return self::CLASS_CONSTRAINT;
+    }
+}