resetTelemetryIdentifiers

Reset internal state in response to application-level telemetry reset.

Consumers should call this method when the user resets the telemetry state of the consuming application, such as by opting out of submitting telemetry. It resets the internal state of the Nimbus client to create a clean break between data collected before and after the reset, including:

* clearing any unique identifiers used internally, so they will reset to
  new random values on next use.
* accepting new randomization units, based on application-level ids that
  may have also changed.
* disqualifying this client out of any active experiments, to avoid submitting
  misleading incomplete data.