Auto-swap phone number for CC for users from Telesign-blocked countries

Context:

1. Users required to verify their identity by providing a phone number have the
option to provide credit card details instead
2. Some countries are blocked (either by us or by Telesign themselves) in
Telesign making users from these countries unable to receive the phone
verification code sent via SMS

Here, we implement auto-swapping of phone number verification requirement for
credit card verification when a user uses a phone number from a Telesign-blocked
country.

This notifies the user (via info alert) that phone number verification is
unavailable and automatically switch them to credit card verification instead.
This should (hopefully) lessen cases where a user is not able to receive the
requested phone number verification code via SMS and have no option but to
contact support to find out why.