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>
Roxie won't have a nodeGroup, it will always write to a single node (afaik). It looks like the wu->addFile code in roxie, will name the roxie as the @cluster.
You won't be able to map that to a 'node group' to return to here though.

I'm not sure about the whole approach or what it exactly it was needed for.
I've just commented in the JIRA and asked for @GordonSmith 's input.