Do not send masked phone numbers to TeleSign. 

This PR ensures that [masked phone numbers](https://github.com/activeprospect/leadconduit-types/blob/bade6bf730c707aa4f7a54faaac83d4588f727a8/spec/phone-spec.coffee#L43-L81) fail TeleSign validation. This means that masked numbers will not be sent to TeleSign. The validation failure reason has also been clarified: it is possible to map the phone number to something other than `phone_1`, therefore the reason was sometimes inaccurate.