[BUGFIX] Prevent catchable error during workspace publishing

When publishing a workspace, incorrect TCA might lead to a catchable
fatal error. This happened, when TCA for a field did not contain a
config-entry.

Resolves: #77619
Releases: master, 8.7, 7.6
Change-Id: I81a3b727320ee984908c964d0729551c4c264f8d
Reviewed-on: https://review.typo3.org/54855


Tested-by: TYPO3com <no-reply@typo3.com>
Reviewed-by: Markus Klein <markus.klein@typo3.org>
Tested-by: Markus Klein <markus.klein@typo3.org>