Login plainly fails if Persistent Auth token has expired or does not exist

[EBhagat]

In the current implementation of Auth interface, if Persistent Auth does not find a valid token to authenticate the user, the account login straight up fails. The developer is required to change the Auth type manually and authenticate once, and then switch back to the Persistent Auth type for the subsequent runs of the game. This could be handled by the Persistent Auth login functionality by providing an alternate default login method (Account Portal, for example) for that specific login, so that the subsequent Persistent Authentication calls can go through. This will make the Persistent Auth functionality more robust.