Bug 31245: Do not call report for job detail view if job not started

Bug 31245: Do not call report for job detail view if job not started

We should not generate the report if the job hasn't started yet

Test plan:
Stop the koha-worker processes, modify a new item using the batch mod
tool, then see the detail page of the job

Without this patch an error is generated:
Can't use an undefined value as an ARRAY reference at /kohadevbox/koha/Koha/BackgroundJob/BatchUpdateItem.pm line 175

Signed-off-by: Andrew <andrewfh@dubcolib.org>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>