Merge "Make common signature system property definitions optional" into main...

Merge "Make common signature system property definitions optional" into main am: b8306086 am: e728051f

Original change: https://android-review.googlesource.com/c/platform/build/+/2609473



Change-Id: Ife1860b73bc83d32a61817d5a9fe25c2deb1e37d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>