Log the correct radio states for GSM_RAT_SWITCHED.

In GsmServiceStateTracker.pollStateDone(), we were recording the
incorrect radio states when logging GSM_RAT_SWITCHED. Specifically,
we were using the new voice radio technology for "network_from" and
STATE_OUT_OF_SERVICE for "network_to".

To avoid confusion when analyzing logs from different devices,
add a new event log tag, GSM_RAT_SWITCHED_NEW, to use for logging
the correct radio states, and add comments to indicate that
GSM_RAT_SWITCHED should be considered obsolete.

Bug: 8781951
Change-Id: I858d3f5044d7fb2560a4e21b8a5b4b14b4689a61