]BUG: SMS Module - should return HTTP 200

https://trello.com/c/tnX99WVb

I have added Response status adnotation to handle method in
InboundSmsController so it will be returning  http 200
when handling will be sucessful. Also added tests to check it.

Change-Id: If02ba9b8284b7ae31232b1a8bd0350bf59c387b2
Merge "]BUG: SMS Module - should return HTTP 200"