[BUGFIX] Respect readOnly for inline relation

If a TCA field is set to readOnly=true and is using the type "inline",
all buttons are now hidden and the fields of the relation are set to
readOnly as well.

Resolves: #56060
Releases: master, 9.5
Change-Id: If2b1cb2be0591d765f40512aaf341a9c26a2f87f
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/61490


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Torben Hansen <derhansen@gmail.com>
Tested-by: Richard Haeser <richard@maxserv.com>
Reviewed-by: Torben Hansen <derhansen@gmail.com>
Reviewed-by: Richard Haeser <richard@maxserv.com>