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

Merge "Make common signature system property definitions optional" into main am: b8306086 am: e728051f am: 13ba580f am: 20dbd142 am: 8dcb5a09

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



Change-Id: I9017b42b1cf0ce59136f8bd5311c69fa455f63e3
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>