[!!!][TASK] Remove GeneralUtility::uniqueList

In #92607, GeneralUtility::uniqueList was migrated
to StringUtility::uniqueList and is therefore now
removed.

Resolves: #96139
Related: #92607
Releases: main
Change-Id: I3eceb459db75a6cb69ed93126516abc2603ba9f6
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/72374


Tested-by: core-ci <typo3@b13.com>
Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>