LibWeb: Return actual callback object from NodeIterator::filter

Author: https://github.com/Lubrsi
Commit: 95949ba8f2
Pull-request: https://github.com/LadybirdBrowser/ladybird/pull/3685
Reviewed-by: https://github.com/gmta ✅

Libraries/LibWeb/DOM/NodeIterator.h

@@ -26,7 +26,7 @@ public:
     bool pointer_before_reference_node() const { return m_reference.is_before_node; }
     unsigned what_to_show() const { return m_what_to_show; }
 
-    NodeFilter* filter() { return m_filter.ptr(); }
+    JS::Object* filter() const;
 
     JS::ThrowCompletionOr<GC::Ptr<Node>> next_node();
     JS::ThrowCompletionOr<GC::Ptr<Node>> previous_node();