[TASK] Document removal of deprecated form config

Various form configuration was deprecated with #96568. This patch adds
a notice about planned removal of those deprecations to the deprecation
message.

Resolves: #97497
Related: #96568
Releases: main
Change-Id: I3e7f16c6bd1eafa1f7db8b23c8fc5cfc89d004c3
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/74479


Tested-by: Björn Jacob <bjoern.jacob@tritum.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: waldhacker <hello@waldhacker.dev>
Reviewed-by: Björn Jacob <bjoern.jacob@tritum.de>
Reviewed-by: waldhacker <hello@waldhacker.dev>