Fix OOB write in authToken2AidlVec am: d78ef2348c

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/keymaster/+/19793608

Change-Id: Id535a0e50f41e8a95c66b3f86859f1601985c23b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>