Merge "Update usage guidelines for UNKNOWN" into main am: 60898fd63f

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/3550899

Change-Id: I5728724a259410d9a282484fef5b125afb4e173c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>