[BUGFIX] Use custom configuration for Install Tool Login mails

As the templates for the FluidEmails are located in EXT:install, the
configuration needs to be adopted.

Resolves: #90345
Releases: master
Change-Id: Ie4b7ea05090b6e77c3cfa4f9714b0a41cc0d57a6
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/63182


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Stefan Froemken <froemken@gmail.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Stefan Froemken <froemken@gmail.com>
Reviewed-by: Benni Mack <benni@typo3.org>