message: Use query_validator instead of query_all_validator to check existence
diff: @@ -24,8 +24,8 @@ pub fn instantiate(
  msg: InstantiateMsg,
  ) -> StdResult<Response> {
  // ensure the validator is registered
  - let vals = deps.querier.query_all_validators()?;
  - if !vals.iter().any(|v| v.address == msg.validator) {
  + let validator = deps.querier.query_validator(msg.validator.clone())?;
  + if validator.is_none() {
  return Err(StdError::generic_err(format!(
  "{} is not in the current validator set",
  msg.validator
  