Revert "redbull: update BOARD_API_LEVEL to T" am: ecd9d22132 am: 66e7f3f4f7

Original change: https://googleplex-android-review.googlesource.com/c/device/google/redbull/+/22788402

Change-Id: I723b3a2f88af5b5933eeeec7912b9662e174e3b7
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>