HPCC-11783 Return NodeGroup in WUInfo ECLResult

The WsWorkunits/WUInfo is updated to return 'NodeGroup'
inside the ECLResult when the result has a 'logicalName'.

Signed-off-by: wangkx <kevin.wang@lexisnexis.com>
@GordonSmith I am guessing that you may get multiple Results, or a specific Result, within one WU. You will not get multiple Results for multiple WUs in one client call. Is that correct?