[omni] Enable CUSTOM_LPH_THRESHOLDS.

This will make our experiment setup easier. See https://docs.google.com/document/d/1GFMqkgVDgFYQnI_JMb7nARuKDwFy1SSVN00YOFKhY1Y/edit?resourcekey=0-JApoPZTfjxke-Cf82RSD_A&tab=t.0#bookmark=id.25pwwrhh1h8q

Bug: 331800576
Test: manual
Flag: legacy CUSTOM_LPH_THRESHOLDS enabled
Change-Id: I4b4fad79151ce6c91ca2895bcff534acae5e340c
1 file changed