Set the priority to the passed arguments over the authentication for balance cmd

Commands allowing to pass a pubkey via the authentication and the usual CLI (balance, and history later (#478)) are prioritizing the authentication methods over the pubkey. @matograine suggested to prioritize the passed argument over the authentication method or return an error.

So you probably always have the --account <account_name> set, and you pass the arguments for which you would like to get info. If no argument is passed, then information would come from the authentication. If none of them is specified, you get an error.