Merge branch '6.1' into 6.2

* 6.1:
  sync message serializer code for forward-compatibility
  skip a test if the mime type detection feature will not work
  minor #47751 Norgweiang translations (ibonkonesa)
  fix overflow issue in WebPprofiler Forms panel

Author: xabbuh

Normalizer/MimeMessageNormalizer.php

@@ -62,7 +62,7 @@ public function normalize(mixed $object, string $format = null, array $context =
         if ($object instanceof AbstractPart) {
             $ret = $this->normalizer->normalize($object, $format, $context);
             $ret['class'] = $object::class;
-            unset($ret['seekable'], $ret['cid']);
+            unset($ret['seekable'], $ret['cid'], $ret['handle']);
 
             return $ret;
         }