Add unique id for sms APIs to be able to trigger correct smstracker

In old APIs the SmsTracker itself was being passed to the RIL
and onSendComplete the tracker's pending intent was triggered
and then the updated messageRef was used as the id.

Instead of passing the tracker, passing a unique id to be used
for the lifetime of the message.

Doing same thing for receiving flow.

Test: None, APIs not exercised yet.
BUG=69846044

Change-Id: Id19f854e2c48649db8f2031ee4f49cdac331451c