[TASK] Have a minor phpstan happification in ext:belog

Resolves: #98397
Releases: main
Change-Id: Id3c3ee0a9de93062840ee0acc39a8c8917326535
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75807


Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>