No need for asking when -a and --login are specified

[akiross]

I just noticed that, when logging in, the program still asks interactively for the phone number even if that was specified as account:

java -jar telegram_backup.jar -a +12345 --login

will ask for the phone number, then the telegram auth code, but the phone number was already specified as command argument. I think the interface could be improved by automatically using the phone number from arguments if present, instead of asking every time.