Auth lib returns null request code on subsequent logins

[wynneplaga]

*Thanks for your interest in the Spotify App Remote SDK!

Issue found on June 1, 2022.

SDK Version: Auth lib 2.0.2

OS Version: Android 12

Steps to reproduce:

1. Open sample app
2. Press "request code"
3. Complete log in
4. Observe successful fetch
5. Press "request code" again
6. Observe tabs open, complete redirect, and close

Expected behaviour:

Code is a valid Spotify code

Actual behaviour:

Code is "null"