Non-canonical cast (boolean) in EmailAttachmentEvaluator is deprecated in PHP 8.4

src/Service/EmailAttachmentEvaluator.php uses a non-canonical (boolean) cast, which PHP 8.4 deprecates in favor of (bool). At line 324: return (boolean) preg_match($pattern, $string);

Under PHP 8.4 this emits the runtime notice "Non-canonical cast (boolean) is deprecated, use the (bool) cast instead". In a Drupal functional test the deprecation is escalated to an error, so any test whose flow evaluates an email attachment condition fails; we hit it when a workflow sends a confirmation email on payment settlement. Changing (boolean) to (bool) resolves it.