Add auto-crop feature for LabelSetImages

Summary:

• Convert assert/crash in the MultiLabel Segmentation view into graceful early-out
• Remove unused header file
• Remove copy of QmitkAutocropAction class. It was copied 1:1 from the segmentation plugin and it was kind of

undeterministic which of the two copies was instantiated at runtime (happy debugging!).

• Add a separate action to auto-crop LabelSetImages. Handling of LabelSetImages is so quirky, that no functionality of the classic auto-crop action or image filters in general can be reused. As we do not want to invest more work than necessary in the ill-formed LabelSetImage data type, I encapsulated/implemented the whole operation

right into the action class, instead of providing a "public" filter.

• Fixes T27386

Test Plan: Tested manually with empty and non-empty 3d and 3d+t LabelSetImages with different numbers of layers and labels with and without having an opened MultiLabel Segmentation view.

Reviewers: O1 MITK Reviewer Group I, kalali

Reviewed By: O1 MITK Reviewer Group I, kalali

Subscribers: kalali

Maniphest Tasks: T27386

Differential Revision: https://phabricator.mitk.org/D351