HPCC-11789 DFU Workunits not showing owners

Fixes HPCC-11789

Modify the grid call from Owners to Users (which is what the response is sending).

Signed-off by: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Merge pull request #6140 from miguelvazq/HPCC-11789

HPCC-11789 DFU Workunits not showing owners

Reviewed-By: Gordon Smith <gordon.smith@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>