T29577 Fixed otsu error with multiple groups and underlying problem (label set cloning is not correct)

Summary:
+ Fixed T29577

Also fixed TotalSegmentator tool which would have the same problem.

Test Plan: code review; application test: use otsu on a label image with multiple groups. Results should be now correctly named and transfered.

Reviewers: O1 MITK Reviewer Group I, kislinsk

Reviewed By: O1 MITK Reviewer Group I, kislinsk

Subscribers: kislinsk

Maniphest Tasks: T29577

Differential Revision: https://phabricator.mitk.org/D829