[TASK] Streamline code in Indexed Search

Various typing issues in Indexed Search
related to the indexer and repository classes
are cleaned up.

Resolves: #102926
Releases: main
Change-Id: Ibf7b0eb9b52ef2d5cca39e17e3328f2605156c6d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82646


Reviewed-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>
Tested-by: Benni Mack <benni@typo3.org>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>
Tested-by: core-ci <typo3@b13.com>