In the STS digitizer, noise is simulated from the previous event time to the current event time. For the first event, noise was simulated from t = 1000 ns (hard-coded) to the first event time.
Since the run start time (default 1000 ns) can be changed by the user, comparison of results with different run start times was difficult.
This MR passes the run start time to the digitizers, and for the STS, the noise simulation now starts at the specified run start time.