[BUGFIX] Element browser is shown instead of Media File Picker

Change-Id: I526dba39cb0d267313bbad5c3b7d215b3cfefcc9
Releases: 3.0.0
Resolves: #56524
Reviewed-on: http://review.typo3.org/31776
Reviewed-by: Fabien Udriot <fabien.udriot@ecodev.ch>
Tested-by: Fabien Udriot <fabien.udriot@ecodev.ch>