[BUGFIX] Ignore empty values for table and uid in FilesContentObject

When using the option "references" as an array, it
is possible to provide table and uid with stdWrap
functionality. The return type can be mixed so
proper casting is necessary.

Also, empty values like an empty string for table or
"0" for uid should not trigger
$pageRepository->getRawRecord and the fallback
values should be used instead.

Another potential bug was found while adding test
cases, where an empty table would result in nothing.
In such a case, the current table should be used for
relation fetching.

Resolves: #96809
Releases: main, 11.5
Change-Id: Ieb90f846bbdafb50190c1d30008aa65e1dbb9e43
Reviewed-on: https://review.typo3.org/c/Packages/TYPO3.CMS/+/73550


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