HPCC-11747 InfoGrid stops monitoring WU after completion

Added extra logic to handle the secnario where a WU completed with Exceptions
and was subsequently restarted and completed with no exceptions.

Fixes HPCC-11747

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #6161 from GordonSmith/HPCC-11747

HPCC-11747 InfoGrid stops monitoring WU after completion

Reviewed-By: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>