[BUGFIX] Show diff for new and delete placeholder records

The workspace module features the element information modal,
which displays, next to the record history, the current version
records' difference to its live record. This difference is now
also displayed for new and delete placeholder records. It's not
reasonable forcing the user to always open the complete record
to have a quick look at the values of e.g. a new record.

Since new / delete placeholders basically contain all fields,
defined in TCA, they are filtered using the FormDataCompiler
to only show the suitable ones.

Resolves: #93620
Releases: master, 10.4
Change-Id: Ib58d568664e3aecb13afa023c0e05f188662811d
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/68156


Tested-by: Christian Kuhn <lolli@schwarzbu.ch>
Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: core-ci <typo3@b13.com>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Christian Kuhn <lolli@schwarzbu.ch>
Reviewed-by: Benni Mack <benni@typo3.org>