Add phone number verification whack-a-mole

Problem/Motivation

A solution to not being able to enforce unique phone numbers on a field/schema level is removing verification of an entity if another entity verifies that number at a later date.

Proposal

Add a setting which removes the pre-existing phone number verification if it is of the same entity type being verified. Like whack-a-mole, but with phone number verifications.

User interface changes

The setting would be found in phone number settings config:

Add checkbox to /admin/config/smsframework/phone_number/%

API changes

Core internals only

Data model changes

Adding config schema

Original

Original comment.