[BUGFIX] Show thumbnails in list module

Add missing checks if type column exists in a row.

Resolves: #56830
Releases: 6.2, 6.1
Change-Id: Ifafdb0c51266c76620696c6d94471b3efddba112
Reviewed-on: https://review.typo3.org/28350
Reviewed-by: Markus Klein
Tested-by: Markus Klein