Tighten cuts on KstGamma line to remove prescale

Tighten the mass cut and kaon PID cuts according to Yingrui's studies on data: https://indico.cern.ch/event/1272210/contributions/5365903/attachments/2640805/4570070/Radiative%20decays%20in%202022%20data.pdf

Current rate is 0.06 ± 0.06 kHz when tested on 15k hlt1 filtered minbias.

Testing again for higher stats, will update numbers here once the nominal HLT1 samples are available