Merge branch '6.4' into 7.3

* 6.4:
  fix test setup
  [Validator] Review Turkish translations
  [Validator] Review Croatian translations
  [Validator] Review translations for Polish (pl)
  use the empty string instead of null as an array offset
  Review translations for Chinese (zh_TW)
  [Serializer] Adjust ObjectNormalizerTest for the accessor method changes from #61097

Author: xabbuh

ResponseHeaderBag.php

@@ -159,7 +159,7 @@ public function getCacheControlDirective(string $key): bool|string|null
 
     public function setCookie(Cookie $cookie): void
     {
-        $this->cookies[$cookie->getDomain()][$cookie->getPath()][$cookie->getName()] = $cookie;
+        $this->cookies[$cookie->getDomain() ?? ''][$cookie->getPath()][$cookie->getName()] = $cookie;
         $this->headerNames['set-cookie'] = 'Set-Cookie';
     }
 
@@ -170,13 +170,13 @@ public function removeCookie(string $name, ?string $path = '/', ?string $domain
     {
         $path ??= '/';
 
-        unset($this->cookies[$domain][$path][$name]);
+        unset($this->cookies[$domain ?? ''][$path][$name]);
 
-        if (empty($this->cookies[$domain][$path])) {
-            unset($this->cookies[$domain][$path]);
+        if (empty($this->cookies[$domain ?? ''][$path])) {
+            unset($this->cookies[$domain ?? ''][$path]);
 
-            if (empty($this->cookies[$domain])) {
-                unset($this->cookies[$domain]);
+            if (empty($this->cookies[$domain ?? ''])) {
+                unset($this->cookies[$domain ?? '']);
             }
         }