Remove empty PersonIdentifier values during denormalization and add isEmpty logic to PersonIdentifierWorker. Include tests for empty value handling.

src/Bundle/ChillPersonBundle/Serializer/Normalizer/PersonJsonDenormalizer.php

@@ -129,6 +129,10 @@ final class PersonJsonDenormalizer implements DenormalizerInterface, Denormalize
 
                 $personIdentifier->setValue($value);
                 $personIdentifier->setCanonical($worker->canonicalizeValue($value));
+
+                if ($worker->isEmpty($personIdentifier)) {
+                    $person->removeIdentifier($personIdentifier);
+                }
             }
         }