When running terraform for adtech setup, it modifies service IAM policy even though service_account_token_creator_list is not set in adtech_setup.auto.tfvars

It is problematic because we are running periodically terraform plan to check if there were no manual modifications in our environment. Unfortunately we need to add some IAM permissions to our service account configured in adtech_setup.aut.tfvars as deploy_service_account_email.

Could you change the terraform script so that if service_account_token_creator_list is not set (or is empty), then you will skip modification of account IAM policy?