[BUGFIX] Ignore empty inputs when creating new folders

When you try to create one of multiple folders in filemodule
and leave one of the new name input fields empty this results
in a non catched exeption.

This change filters out the empty input fields and gives a
error message when no name is given.

Resolves: #56034
Releases: 6.2
Change-Id: I1d341d1b7951dc8e8fe64190168f8b71c6f75676
Reviewed-on: https://review.typo3.org/27651
Reviewed-by: Wouter Wolters
Tested-by: Wouter Wolters
Reviewed-by: Anja Leichsenring
Tested-by: Anja Leichsenring