Prevent auto repeat mode from infinite loop
Prevent auto repeat mode from infinite loop

Summary: Do not set new position if no slices are available for scrolling

Test Plan:
manual testing
- open MITK workbench
- enable PACS mode
- scroll over the limits (0) using the mouse wheel
- MITK does not freeze anymore
	- compare to latest develop including D538
- load an image
- scroll over the limits using the mouse wheel
- auto-repeat wraps around the limits

Reviewers: kislinsk, O1 MITK Reviewer Group I, floca

Reviewed By: O1 MITK Reviewer Group I, floca

Subscribers: floca, kalali, kislinsk

Maniphest Tasks: T24635

Differential Revision: https://phabricator.mitk.org/D558

MITK/MITK,MITK/MITK,MITK/MITK,MITK/MITK,MITK/MITK,MITK/MITK