Adds a Caller ID to the account and places a verification call to it; the call reads out a verification code to submit with the verify method. cli is the phone number in E.164 format. Calling this again for a Caller ID that is not verified yet places a new verification call. The number of verification calls is limited per number and per account; once the limit is reached the request is rejected until later. Returns 422 with errors when the Caller ID can't be added or the call can't be placed.