OAuth 2 Bug: Grant Code not automatically detected in Redirect URI after successful authentication

After a successful authorization, the app that we are authenticating into with OAuth2 redirects to the Redirect URI supplied and appends the grant code in the `code` query string param. Insomnia is not displaying any signs that it has successfully noticed the redirect and grabbed the code from the redirect URI.

Here is a screencast demonstrating the problem. I had to blur out some sensitive info, but it gets the idea across.

https://user-images.githubusercontent.com/700803/110540006-32043480-80e3-11eb-9e78-90f65cafc869.mp4

Start by reproducing the OAuth2 authorization flow shown in the screencast, focusing on the supplied Redirect URI and the returned `code` query parameter. Trace where the app should notice the successful redirect and capture the grant code; done means the code is automatically detected after authentication.

Written by the indexing model from the issue text.