minor #19497 [Validator] Fix dockblock typehint in XmlFileLoader (tgalopin)

This PR was merged into the 2.7 branch.

Discussion
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[Validator] Fix dockblock typehint in XmlFileLoader

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Commits
-------

92b3ef4 [Validator] Fix dockblock typehint in XmlFileLoader

Author: nicolas-grekas

Mapping/Loader/XmlFileLoader.php

@@ -182,13 +182,7 @@ protected function parseFile($path)
         return simplexml_import_dom($dom);
     }
 
-    /**
-     * Loads the validation metadata from the given XML class description.
-     *
-     * @param ClassMetadata $metadata         The metadata to load
-     * @param array         $classDescription The XML class description
-     */
-    private function loadClassMetadataFromXml(ClassMetadata $metadata, $classDescription)
+    private function loadClassMetadataFromXml(ClassMetadata $metadata, \SimpleXMLElement $classDescription)
     {
         if (count($classDescription->{'group-sequence-provider'}) > 0) {
             $metadata->setGroupSequenceProvider(true);