When something goes wrong during registration, we always show an Alert in registrationServerCall.

When registrationServerCall is called from FullscreenSIWEPanel, we want to call goBackToPrompt if it fails, after the user acknowledges the prompt.

Depends on D12082

1. Force a client_version_unsupported failure by hardcoding it in keyserver/src/session/version.js
2. Disable enableNewRegistrationMode
3. Enable usingCommServicesAccessToken
4. Try FullscreenSIWEPanel with a wallet that hasn't been registered before
5. Verify that goBackToPrompt is called after acknowledging the Alert