Fix oauth_token auth request to avoid MissingDroidguard error

[tyr7z]

Google appears to have recently started enforcing the MissingDroidguard check on the oauth_token endpoint. This error was initially triggered sporadically but now seems to be consistently enforced.

This change fixes the issue by explicitly adding droidguard_results=null to the auth request. Including this parameter prevents the server from rejecting the request with the MissingDroidguard error.

My assumption is that the issue started appearing due to a gradual rollout of updates on Google's infrastructure. As their servers are updated incrementally to maintain availability, some requests likely began hitting updated nodes earlier than others, which explains the intermittent errors observed in previous weeks.

[Yakov5776]

My assumption is that the issue started appearing due to a gradual rollout of updates on Google's infrastructure. As their servers are updated incrementally to maintain availability, some requests likely began hitting updated nodes earlier than others, which explains the intermittent errors observed in previous weeks.

Most likely was A/B testing, but thank you for this patch!