[DOCS] Adjust removal version of switchable controller actions

Switchable controller actions are removed with TYPO3 12.0. The deprecation
note is adjusted to reflect it.

Resolves: #97523
Related: #89463
Related: #96282
Releases: main, 11.5, 10.4
Change-Id: Iad04bbb573f2b87ce87a8faabe25c97a8812f937
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74463


Tested-by: core-ci <typo3@b13.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Oliver Bartsch <bo@cedev.de>