Strip ODM_MANIFEST_SKUS

Otherwise it gets a different value when using starlark
board config, causing the ninja files to differ.

Bug: 201700692
Test: ./build/bazel/ci/rbc_regression_test.sh -b aosp_crosshatch_car-userdebug
Change-Id: I55870f031b779202db720f10d7d502f9d868e1f6