Migrate to new open-dice API for Android am: adcd10f9f2

Original change: https://android-review.googlesource.com/c/trusty/app/sample/+/2717997

Change-Id: I3529f65c1c58baa57f3d0f7d2f7eb0f797d22803
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>