1. Tested `isValidSIWENonce` regex with some simple unit tests.
2. Made sure `landing` generally continues to work as expected on desktop (no nonce).
3. Made sure `landing/SIWE` continues to work as expected on `native`.
4. Messed up the `nonce` in the request to `landing/SIWE` (hardcoded to some gibberish) and ensured that we got a `400` in response.