[Thinkit] Improve factory reset tests, gNMI breakout tests, Update Finish to read all of the messages in the stream channel before Finishing it, Utility library cleanup & Add support to get counters.

[Thinkit] Improve factory reset tests, gNMI breakout tests, Update Finish to read all of the messages in the stream channel before Finishing it, Utility library cleanup & Add support to get counters. #4443