[TASK] Remove superfluous cast in LiveSearch

Used command:

> ./Build/Scripts/runTests.sh -s phpstanGenerateBaseline

Resolves: #98008
Releases: main, 11.5
Change-Id: Iecadad3cc1e5089f0ab7282f5b5302ead66ce6a7
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/75270


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Oliver Klee <typo3-coding@oliverklee.de>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>