Upgrade code from 146 to new standards

src/Bundle/ChillCustomFieldsBundle/CustomFields/CustomFieldChoice.php

@@ -366,7 +366,7 @@ class CustomFieldChoice extends AbstractCustomField
      * If the value had an 'allow_other' = true option, the returned value
      * **is not** the content of the _other field, but the `_other` string.
      */
-    private function guessValue(array|string|null $value)
+    private function guessValue(null|array|string $value)
     {
         if (null === $value) {
             return null;