HPCC-12080 Fix codegen JSON formatting for Sets of "All"

Signed-off-by: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
Merge pull request #6341 from afishbeck/codegenJsonSetsWithAll

HPCC-12080 Fix codegen JSON formatting for Sets of "All"

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>