Revert "[TASK] Deprecate f:format.html in the backend context"

This patch will be reverted, because the ViewHelper is still in use
and an alternative is not ready yet.

This reverts commit 0a59b275.

Releases: master
Resolves: #80620
Reverts: #72716
Change-Id: I9667dbc2acd3fec0ed9af29ae995fb6f25aaae92
Reviewed-on: https://review.typo3.org/52306


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Frank Naegler <frank.naegler@typo3.org>
Tested-by: Frank Naegler <frank.naegler@typo3.org>
Reviewed-by: Benni Mack <benni@typo3.org>
Tested-by: Benni Mack <benni@typo3.org>