[TASK] Declare strict types in ext_localconf.php files

Since #94739 it's possible to declare strict types
in ext_localconf.php files. This patch does this
through the core.

Resolves: #94981
Related: #94739
Releases: master
Change-Id: I61a937a487d5d065daccc58ca997a1ffd80f9d35
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/70743


Tested-by: core-ci <typo3@b13.com>
Tested-by: Wouter Wolters <typo3@wouterwolters.nl>
Tested-by: Andreas Fernandez <a.fernandez@scripting-base.de>
Reviewed-by: Wouter Wolters <typo3@wouterwolters.nl>
Reviewed-by: Andreas Fernandez <a.fernandez@scripting-base.de>