[BUGFIX] Respect workspace in ajax slug generation

The SlugHelper now receives the current workspace id and applies the
correct workspace constraint.

Resolves: #96853
Releases: main, 11.5
Change-Id: I3ab2bf850a5fa63300f6715a6dca9c223f524670
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74298


Tested-by: core-ci <typo3@b13.com>
Tested-by: Stefan Bürk <stefan@buerk.tech>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Stefan Bürk <stefan@buerk.tech>
Reviewed-by: Benni Mack <benni@typo3.org>