HPCC-12625 Fix regression in last commit for this issue.

Sub-subscriptions broken by last commit

Signed-off-by: Jake Smith <jake.smith@lexisnexis.com>
Merge pull request #6704 from jakesmith/hpcc-12625b

HPCC-12625 Fix regression in last commit for this issue.

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>