[TASK] Strictify UnitTests part 1

The following core extensions are handled:

* EXT:scheduler
* EXT:seo
* EXT:setup
* EXT:t3editor
* EXT:workspaces

Resolves: #94850
Releases: master
Change-Id: Ia3e7138a2c4babbcf4428a9a3e5d64de81262687
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70503


Tested-by: core-ci <typo3@b13.com>
Tested-by: Marcin Sągol <marcin@soee.pl>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Marcin Sągol <marcin@soee.pl>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>