[pinot] add more log when result parsing fails

thirdeye-plugins/thirdeye-pinot/src/main/java/ai/startree/thirdeye/plugins/datasource/pinot/PinotQueryExecutor.java

@@ -173,6 +173,7 @@ private static ThirdEyeDataFrameResultSet fromPinotResultSet(final ResultSet res
         try {
           valueString = resultSet.getString(rowIdx, metricColumnIdx);
         } catch (final Exception e) {
+          LOG.error("Failed to get value as String from result set. Replacing with a null value. This may generate errors downstream. Please reach out to support.", e);
           // Do nothing and subsequently insert a null value to the current series.
         }
         columnsOfTheRow[metricColumnIdx + groupByColumnCount] = valueString;