Converts object of class `DataCombined` to data.table with attributes.
convertDataCombinedToDataTable.RdFormat corresponds to `data.table` produced by `readObservedDataByDictionary`.
See also
Other observed data processing:
addBiometricsToConfig(),
aggregateObservedDataGroups(),
convertDataTableToDataCombined(),
readObservedDataByDictionary(),
updateDataGroupId(),
updateOutputPathId(),
validateObservedData()