Ladybird: Implement notify_request_open_new_tab

Author: https://github.com/kalenikaliaksandr
Commit: 640864b32e
Pull-request: https://github.com/SerenityOS/serenity/pull/17855
Reviewed-by: https://github.com/linusg
Reviewed-by: https://github.com/trflynn89 ✅

Ladybird/WebContentView.cpp

@@ -977,6 +977,9 @@ void WebContentView::notify_server_did_close_browsing_context(Badge<WebContentCl
 
 String WebContentView::notify_request_open_new_tab(Badge<WebContentClient>)
 {
+    if (on_new_tab)
+        return on_new_tab();
+
     return {};
 }