Merge "Document the allowed challenge size" into main am: 4f73689e am: bcd81f14 am: f5c11587

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



Change-Id: I8d1e02349b942325a40f345f47904fd05a8f9f3c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>