Merge "Clarified that USER_IDENTIFICATION_ASSOCIATION is optional." into rvc-dev am: b35c0cd494 am: cf9aeeee17

Original change: https://googleplex-android-review.googlesource.com/c/platform/hardware/interfaces/+/11796048

Change-Id: I301bcbc18dd42a7f1e7d09f2c6cf75a020672e3d