use Laminas\Form\ElementInterface;
use Laminas\View\PhpRenderer;

$escapeMessages = function (ElementInterface $formOrElement, PhpRenderer $renderer): void {
    $messages = $element->getMessages();
    if (! $messages) {
        return;
    }

    $escaped  = [];
    array_walk_recursive(
        $messages,
        static function (string $item) use (&$escaped, $renderer): void {
            $escaped[] = $renderer->escapeHtml($item);
        }
    };

    $element->setMessages($escaped);
};

// Usage with a form
// $this is the view renderer
$escapeMessages($form, $this);

// Usage with a fieldset
// $this is the view renderer
$escapeMessages($fieldset, $this);

// Usage with a form element
// $this is the view renderer
$escapeMessages($element, $this);