HPCC-11720 Downgrade error to warning in layout translation code

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #6086 from ghalliday/issue11720

HPCC-11720 Downgrade error to warning in layout translation code

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>