QA WAR - cli somehow writes NULL into config file

[cdhanna]

various people at different times have encountered an issue where Unity using the CLI (server) somehow caused the .beamable/config.beam.json file to contain the string NULL. When this happens, any CLI invocation (server or proc) causes an infinite loop trying to talk to the auth server.

1. when the state is invalid, we should present a clean error.
2. we should not ever get into this state via Unity.