fix: confirm cost before enabling paid mfa addons

[sweatybridge]

What kind of change does this PR introduce?

Bug fix

What is the new behavior?

Avoids bill shock when user accidentally enables paid addons from config push.

Additional context

...
Enabling Advanced MFA - Phone will cost you $75/month, then $10/month. Keep it enabled? [Y/n] n
Enabling Advanced MFA - WebAuthn will cost you $75/month, then $10/month. Keep it enabled? [Y/n] n
Updating Auth service with config: diff remote[auth] local[auth]
--- remote[auth]
+++ local[auth]

[avallete]

Code looks good.

FMI how does it work for branches ? Enabling those for branches does also incurs extra cost on top of the project ? Is it included ?

I'm wondering if a user might mistakingly activate the options on every branches just because it use a single config.toml between branching/prod 🤔