"Checking if a phone number has been already used."

[pareschi]

Hello team(@kwhinnery, @atbaker, @dprothero, @ktoraskartwilio, @ayyrickay, @elizabethsiegle )

I've just added a new phone check. If anyone is trying to create another user using the same number during the demo, an error will pop up to the audience.

Thanks,
Luiz Pareschi