[BUGFIX] Follow-up: Description-field for scheduler-jobs

Add the new field to the list of fields to be save during task
creation.

Resolves: #52696
Releases: 6.2
Change-Id: I4c281535a22318a6a742b25c6196a511bc620e24
Reviewed-on: https://review.typo3.org/24630
Reviewed-by: Philipp Gampe
Tested-by: Philipp Gampe