Merge changes from topic "revert-3195644-revert-3195637-revert-3184480-system_build_prop_soong-BZIDUTEOOC-KRUETCBWUR-TUHZPHUVFJ" into main

* changes:
  Revert "Revert^2 "Add more variables for system/build.prop migra..."
  Revert^3 "Use Soong-built system/build.prop"