Explicitly keep default constructor in rules without members am: 96af708145

Original change: https://android-review.googlesource.com/c/platform/packages/apps/Messaging/+/3438699

Change-Id: Ic7a716a9384ebc40499b03980fe3317ad6e741c3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>