ExportRecordsAsync in csv uses the rawOrLabelHeaders instead of rawOrLabel

[jlewis99]

ExportRecordsAsync in csv uses the rawOrLabelHeaders instead of rawOrLabel

lines 3250 and 3372 and 3487 in RedcapApi.cs

            // Pertains to CSV data only
            var _rawOrLabelValue = rawOrLabelHeaders.ToString();
            if (!IsNullOrEmpty(_rawOrLabelValue))
            {
                payload.Add("rawOrLabel", _rawOrLabelValue);
            }

---

should be:

            // Pertains to CSV data only
            var _rawOrLabelValue = rawOrLabel.ToString();
            if (!IsNullOrEmpty(_rawOrLabelValue))
            {
                payload.Add("rawOrLabel", _rawOrLabelValue);
            }