HPCC-10237 Don't move CHOOSEN() over a grouped count project

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #5048 from ghalliday/issue10237

HPCC-10237 Don't move CHOOSEN() over a grouped count project

Reviewed-By: Jamie Noss <james.noss@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>