fix for online NoiseBurst flagging inefficiency

As described in details in ATR-27613, a inefficiency was found in the online flagging of Noise Bursts. The fix (or better say, the improvement) is rather simple. This was not only tested locally but also tested by changing the same parameter online, not provoking any increase in rate and increasing the flagging efficiency as reported by LAr DB expert @pavol. HLT operations responsible @shanisch is also on top of this and requested that we take the "by hand" modification of the parameter to a MR. This is, I believe, urgent to hit P1 (even if through a patch).