HPCC-10521 Fix incorrect prototype for the workunit stats plugin

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #5196 from ghalliday/issue10521

HPCC-10521 Fix incorrect prototype for the workunit stats plugin

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>