[TASK] Drop TYPO3_MODE usage in ext:adminpanel ext_localconf.php

Code in ext_localconf.php must not create different
framework state depending on the (frontend or backend)
application type. The ApplicationType helper class does
not work at this point in bootstrap, since the PSR-7
request object has not been created, yet.

Solution is to always register the admin panel logger,
and to decide within the logger instance if an incoming
log record should be handled.

Resolves: #92952
Related: #92951
Related: #92947
Releases: master
Change-Id: If0834abff33d5ed1fa4f0e18c0f76c252db4013c
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/66943


Reviewed-by: Simon Gilli <typo3@gilbertsoft.org>
Reviewed-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Reviewed-by: Daniel Haupt <mail@danielhaupt.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Anja Leichsenring <aleichsenring@ab-softlab.de>
Tested-by: Daniel Haupt <mail@danielhaupt.de>
Tested-by: Simon Gilli <typo3@gilbertsoft.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>