Merge "Document the allowed challenge size" into main am: 4f73689e26 am: 05c01de859 am: dd73901807

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2813217

Change-Id: I6dbb8cd4f81455c7a7673e4fd4d0da2fb46d6551
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>