LibWeb: Don't use a JS::Handle for XHR response object

Author: https://github.com/awesomekling
Commit: 8f4ea4e308
Pull-request: https://github.com/SerenityOS/serenity/pull/14816
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWeb/XHR/XMLHttpRequest.h

@@ -106,7 +106,7 @@ private:
     enum class Failure {
         /// ????
     };
-    Variant<JS::Handle<JS::Value>, Failure, Empty> m_response_object;
+    Variant<JS::Value, Failure, Empty> m_response_object;
 
     // https://xhr.spec.whatwg.org/#override-mime-type
     Optional<MimeSniff::MimeType> m_override_mime_type;