Update ShannonIms CERTIFICATE to PRESIGNED am: 794f6831d7

Original change: https://googleplex-android-review.googlesource.com/c/device/google/bluejay/+/25300807

Change-Id: I3a0e79431fd044eb44a3aceea09f7dd2ffb6858e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>