Bug fix and cleanup of BandwidthMonitor

Current version of DAQ/DAQUtils/src/BandwidthMonitor.cpp has a bug where the "per WG" histograms are not filled with exclusive decision events (events that passed only one line). Not a major issue since these events are still counted in the exclusive decision histograms, so we can get the correct bandwidth from current algorithm.

This MR fixes this bug and removes some unnecessary features (we actually don't need to count the events that don't pass the lines).