Enhance validate phone number method

[andhikaribrahim]

Issue

For some cases, if phone number submitted like these examples:

String phoneNumber = "6282211110234";
String phoneNumber = "082211110234";
String phoneNumber = "006282211110234";

String phoneNumber = "82211110234";

Our API will throw "Invalid api_key/signature" error.

[pangtongs]

Needs testing / proof this works.