Update datagram transfer state.

The following changes are made in this CL:
DatagramDispatcher: updates DatagramController about datagram send status.
- Datagram transfer state is initially set to SENDING when sendSatelliteDatagram() is called, then:
-- State changes to SEND_FAILED on error
-- State changes to SEND_SUCCESS if one datagram is sent successfully
-- State Changes to IDLE if pendingDatagramCount is 0

DatagramReceiver: updates DatagramController about datagram receive status.
- Datagram transfer state is initially set to RECEIVING when pollPendngSatelliteDatagrams() is called, then:
-- State changes to RECEIVE_NONE if pendingCount is 0 and received datagram is null
-- State changes to RECEIVE_SUCCESS if received datagram is not null
-- State changes to IDLE if pending count is 0

DatagramController:
- Stores all the variables needed to update onSendDatagramStateChanged(), onReceiveDatagramStateChanged() and calls PointingAppController where there is change in datagram transfer state.

Bug: 269637555
Test: atest SatelliteManagerTest, Flashed build on raven-userdebug: calls and SMS are working.
Change-Id: Iabb4c805380b0303c922b154817824758fad9dba