HPCC-9236 WU Lists calling the server for each row

WUQueryWidget and GetDFUWorkunitsWidget were making an extra call for each row item to the server.

Fixes HPCC-9236

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #4333 from GordonSmith/HPCC-9236

HPCC-9236 WU Lists calling the server for each row

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>