[BUGFIX] Catch exception in filelist when file is missing

The code responsible for rendering the thumbs belonging to a
record doesn't catch the exceptions when a file couldn't be found.

This change adds a try catch around the functions that
tries to retrieve the file and displays a flash message when
the file is missing.

Resolves: #56077
Releases: 6.2
Change-Id: Icc6550db43c8738c74fd7ea8faac6e99a54bc0f3
Reviewed-on: https://review.typo3.org/28284
Reviewed-by: Markus Klein
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Georg Ringer
Tested-by: Georg Ringer