[automerger skipped] Handle case where NN AIDL callback is null in IDevice::prepareModel* am: 7c0353f8e4 -s ours am: fa712a0efb -s ours

am skip reason: Merged-In I4a15d02c4879a0261ec26cc0e7a47d0a4da86b8b with SHA-1 d6f6d01499 is already in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/hardware/interfaces/+/18102697

Change-Id: I1842ab0782cbf3d21ee8f27d797545a094f34f94
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>