[BUGFIX] Prevent exception for invalid file link

Using an invalid uid to link to a file
does no longer throw an exception, since
this prevents the backend user from fixing
the invalid entry, because the edit form
can no longer be accessed.

Resolves: #102670
Releases: main, 12.4
Change-Id: I634eb88a2ddf671abbb88870d664e739e8127ce9
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/82212


Tested-by: Oliver Bartsch <bo@cedev.de>
Tested-by: core-ci <typo3@b13.com>
Reviewed-by: Oliver Bartsch <bo@cedev.de>