Now you've confused me...
Pooh seems to confirm what the rest of the thread says - you have to use the website not the app.
The "VQ code", "QR code", and the website are the same thing.
I count three ways you can do this:
1. You can walk back to the HP area, find the QR code sign, and scan it. Or maybe find it elsewhere in the park.
2. You can pull up the first post in this thread, open the link to the initial Twitter post and scan the code from there (not easy, but it works),
3. Just open this link on your phone right now -
https://vltest.universalorlando.com/#
All three do
the same thing, but #3 is, by far, the easiest. I also recommend that you go to that site, set up an account, and bookmark it (or however you want to make sure you have access to it when you need it)... and do it right now. There's no reason not to.
Unless something changes between now and your trip, don't look for Hagrid's virtual queue reservations in the Universal app... go to the site above. And keep in mind... this really could all change again tomorrow