Merge "Add `BUILDING_VENDOR_IMAGE` to soong_config_variable." into main am:...

Merge "Add `BUILDING_VENDOR_IMAGE` to soong_config_variable." into main am: c676a38c am: 5e81254a

Original change: https://android-review.googlesource.com/c/platform/build/+/3405279



Change-Id: I8e78e133abaf16689c3e7a6759c17f4b40795854
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>