B2OC: Tighten cuts for LbToDpDmPK line

Tighten cuts for the LbToDpDmPK_DpToHHH line as requested by the proponents.

The retention was reduced from 7/146344 to 2/146344 from tests on 2024 data.

Hopefully this will alleviate the multiple candidate issue.

cc @lzhang @squ @abertoli