[BUGFIX] Use language overlay for image rendering

In the image rendering TypoScript configuration of css_styled_content
the uid is removed from the references configuration of the FILES
content object.

This makes sure that the language overlay mechanism from the FILES
content object is used.

Resolves: #56712
Releases: 6.2
Change-Id: Iaea43ca006826facfba40a846da67704dd3154ea
Reviewed-on: https://review.typo3.org/28210
Reviewed-by: Xavier Perseguers
Tested-by: Xavier Perseguers
Reviewed-by: Markus Klein
Tested-by: Markus Klein