HPCC-12442 Fix compile warnings from implicit type casts

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6551 from ghalliday/issue12442

HPCC-12442 Fix compile warnings from implicit type casts

Reviewed-By: Jamie Noss <james.noss@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>