Allow rbc_product_config.sh to test only the board config aosp_cf_arm64_auto-userdebug is an example of a product that has a working RBC board configuration, but a failing product configuration. Update the CI script to allow testing board configuration without product configuration. Bug: 200840916 Test: Manually Change-Id: I80a1452fc4e1c3c03ae7b071eca9b33036a2c9d8