Tighten D2hhPi0 resolved lines

This MR tightens the PT cuts on resolved Pi0 and the child photons from 500/150 MeV to 750/350 MeV.

The attached plot is from a recent ANA prod of these lines, red is events passing the cut. This removes >85% of all events with what looks to be a very high signal efficiency. Note that while this will impact the efficiency at the Dalitz corners somewhat, tightening HLT1 would likely impact it more in particular as these decays only have two charged tracks so HLT1 is a largely exclusive trigger for them.

@tpajero @fbetti @lpica @aanelli @cacochat