In v11, extension authors were able to enhance the site configuration
"TCA" with richtext fields. Since v12, this is not possible anymore due
to the missing `backend.form` imports, required to load necessary
JavaScript modules tagged as such. This commit adds the missing
instruction, allowing to make use of ckeditor and related modules
again.

Resolves: #103115
Releases: main, 12.4
Change-Id: I2fb6d6b917ee99d9616593f118daa72d3f3a460b
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/83000


Reviewed-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Garvin Hicking <gh@faktor-e.de>
Reviewed-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Garvin Hicking <gh@faktor-e.de>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Andreas Kienast <a.fernandez@scripting-base.de>
Reviewed-by: Benjamin Franzke <ben@bnf.dev>
Tested-by: Oliver Bartsch <bo@cedev.de>