auto-brightness: Change light debounce for R4/O6

This reduces the brightening and darkening light debounce
configuration to match R3 and earlier Pixel devices.

Bug: 185770517
Test: Verified "dumpsys display" shows correct config values.
      Verified brightness transitions are similar to R3 now.

Change-Id: I6bd47cb52c28c63ece6b5247344a6cf062eb31ea
2 files changed