fix: include gender and nationality into group of mandatory fields

src/Form/Model/ParticipantDto.php

@@ -52,7 +52,11 @@ class ParticipantDto
     #[Assert\NotBlank(message: 'Bitte angeben', groups: ['strict_required'])]
     public ?string $lastName = null;
     public ?string $title = null;
+
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['strict_required'])]
     public ?string $gender = null;
+
+    #[Assert\NotBlank(message: 'Bitte angeben', groups: ['strict_required'])]
     public ?string $nationality = null;
 
     public ?string $height = null;