message: Make delegator entries optional.
diff: @@ -230,6 +230,7 @@ impl FromBytes for DelegatorConfig {
  #[derive(PartialEq, Eq, Serialize, Deserialize, DataSize, Debug, Clone)]
  pub struct AccountsConfig {
  accounts: Vec<AccountConfig>,
  + #[serde(default)]
  delegators: Vec<DelegatorConfig>,
  }
  