Fix lunch choices for git_main am: 887a76e65a

Original change: https://android-review.googlesource.com/c/device/google_car/+/2811004

Change-Id: I84df0776fbfdd471ba6ed592396bb5dce887559c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>