Merge "Metadata tool correction: Output empty proto in case of no input" into main am: 51665cf0

Original change: https://android-review.googlesource.com/c/platform/build/+/2906355



Change-Id: I5dd8f9271716e4fb648ad8772b772dfaa6f9bf8c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>