* Activity log not working

Old issue fixed by Martin in 2022 but never committed.
In short, users can't see the "activity log" of 3.2 submissions.
Patched and tested in 3.3.0-19 without any collateral effect.

Full description here:
https://forum.pkp.sfu.ca/t/activity-log-not-work/71271/9

* Update PKPSubmissionFileService.inc.php

Error in the patch detected by Kaitlin's review.
Apply the changes requested.