Use android::binder::unique_fd am: ee9e3304d7

Original change: https://android-review.googlesource.com/c/trusty/app/cast-auth/+/2853549

Change-Id: I0f1bfaf300b0d062fbc08464553c83c153380688
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>