message: Add pause in iOS interaction test.
diff: NSNumber *from = timestamp;
  NSNumber *to = @([from intValue] + 200);
  + [NSThread sleepForTimeInterval:3];
  +
  ret = [[LedgerUtils sharedInstance] buildGetRevocRegDeltaRequestWithSubmitterDid:proverDid
  revocRegDefId:credentials_for_attr_1[@"cred_info"][@"rev_reg_id"]
  from:from
  