INFRA-18260: Use parseTokenInternal to avoid setting default token

[mattclement]

Description

parseToken sets the default token if none are included. My testing with consul agent -dev didn't have a default token, so this behavior was missed.

Testing & Reproduction steps

config.hcl

log_acl_info = true
log_json = true
acl {
  tokens {
    default = "asdf"
  }
}

Build and run against the above file: consul agent -dev -config-file config.hcl

With this patch, curl localhost:8500/v1/kv/foo correctly emits the log indicating a missing ACL token. Without the patch, no log is emitted.