[BUGFIX] SQL error in some MM workspaces discard scenarios

Depending on SQL structure of an MM table, the recent fix for
issue #93064 can lead to query errors: It works with core
category relations but fails for instance with ext:news
'related news' relations. This is due to an assumption
about existence of field 'tablenames', which is bogus.
If needed, the according where restriction comes from TCA
MM_match_fields already, which is sufficient.

Resolves: #93109
Related: #93064
Releases: master, 10.4
Change-Id: Ifcc15989f87119cfb10c2da47c22b42a0dd4558a
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/67188


Tested-by: TYPO3com <noreply@typo3.com>
Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: Sebastian Michaelsen <michaelsen@t3seo.de>
Tested-by: Benni Mack <benni@typo3.org>
Reviewed-by: Oliver Bartsch <bo@cedev.de>
Reviewed-by: Sebastian Michaelsen <michaelsen@t3seo.de>
Reviewed-by: Benni Mack <benni@typo3.org>