[TASK] Improve usage of Backend RequestHandler

The backend request with the cli check is dead code
since a different application is used for cli.

Resolves: #85662
Releases: master
Change-Id: Icea2667e9369c4041094eaa53283c6c59b3e9dd7
Reviewed-on: https://review.typo3.org/57695


Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>