HPCC-12515 no_datasetfromrow should always traverse input

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
HPCC-12515 Minor changes following review

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6626 from ghalliday/issue12515

HPCC-12515 no_datasetfromrow should always traverse input

Reviewed-By: Jamie Noss <james.noss@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>