Change criteria for phone number validation in CDB3

Existing rule is ^[+][0-9]+$ Change rule so that phone numbers can start from "0"

This is a request from a broker. It is not possible to use phone number 0 800 during registration. And as for now one of mobile operators does not support calling to toll-free numbers by dialing +380800. Thus it is worth changing validation criteria so that phone number during registration could begin from 0 as well.