FS-9979: [verto.js] When verto client rejects a call returns hangup cause NORMAL_CLEA...

FS-9979: [verto.js] When verto client rejects a call returns hangup cause NORMAL_CLEARING #comment passing neither cause or causeCode will result in normal clearing, passing either one of cause or causeCode will result in that value being passed and parsed on the server side, if the cause is valid it will be accepted otherwise it will try to validate causeCode instead, if neither are true it defaults to normal clearing #resolve