[BUGFIX] Only select current file when editing metadata

Only select the current file connected to the metadata when editing the
metadata of a file.

Resolves: #78845
Releases: master, 8.7, 7.6
Change-Id: Ib65b1e1aaae1fa2c93b03e4865582841a28990a6
Reviewed-on: https://review.typo3.org/55168


Reviewed-by: Jigal van Hemert <jigal.van.hemert@typo3.org>
Tested-by: Jigal van Hemert <jigal.van.hemert@typo3.org>