Change default of HGTD digi to use only current bunch crossing

To further address the issue of hits from other BCs (see also MR 52744), I am changing here the default config of the HGTD digi to only use the current BC. This can alternatively be done in config alone, so to be discussed in USI if we want this in. Opening the MR anyway to quickly have the ability to choose (as discussed with @tstreble).

Tagging also @tadej, @dshope, @cohm, @wyswys