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>
NB: There's an existing issue, HPCC-11733, that covers moving existing methods that are environment related out of workunit and into environment.

_If_ we end up adding another one as result of this issue, the functionality should be added there.