feat: use normalized checkbox values in field handlers

src/Form/Service/ParticipantInsuranceFieldHandler.php

@@ -334,7 +334,7 @@ class ParticipantInsuranceFieldHandler extends AbstractParticipantFieldHandler
 
         // Check if bulk insurance booking is enabled
         $bulkInsuranceBooking = $applicantData['bulkInsuranceBooking'] ?? false;
-        if (false === (bool) $bulkInsuranceBooking) {
+        if (false === $this->normalizeCheckboxValue($bulkInsuranceBooking)) {
             return false;
         }