Confirm 2FA is working before enabling it on account

[PMaynard]

Make sure that the user has correctly added 2FA before enabling it on their account.

For example I can not access my account because I enabled 2FA but did not add it to my 2FA app.

[lwward]

Instead of adding another step it might be nicer to confirm on next login. Next time (or next few times) the user logs in allow them to disable 2FA.

[PMaynard]

Normally when you first configure 2FA they ask to enter a code just like when you login, if it matches all is good, if not we know their device is not working.

[lwward]

I was trying to avoid any extra steps where they could be avoided, but seeing as they will already have the app open in front of them it's no effort