Refactor array filter callbacks in Denormalizers

This commit changes the array filter callbacks used in PublicKeyCredentialOptionsDenormalizer and PublicKeyCredentialUserEntityDenormalizer. The old and new conditions ensure that only values that aren't null pass through, whereas previous conditions also checked against empty arrays. The callbacks have also been updated to include return type declarations for better type safety.

src/webauthn/src/Denormalizer/PublicKeyCredentialOptionsDenormalizer.php

@@ -174,6 +174,6 @@ public function normalize(mixed $data, ?string $format = null, array $context =
             ];
         }
 
-        return array_filter($json, static fn ($value) => $value !== null && $value !== []);
+        return array_filter($json, static fn ($value): bool => $value !== null);
     }
 }

src/webauthn/src/Denormalizer/PublicKeyCredentialUserEntityDenormalizer.php

@@ -57,7 +57,7 @@ public function normalize(mixed $data, ?string $format = null, array $context =
             'icon' => $data->icon,
         ];
 
-        return array_filter($normalized, fn ($value) => $value !== null);
+        return array_filter($normalized, static fn ($value): bool => $value !== null);
     }
 
     public function supportsNormalization(mixed $data, ?string $format = null, array $context = []): bool