T27477 Improved_node_selection_preference_page_default_settings

Summary:
Added better default behavior if no preferences are set so far. It is now directly implemented in the helper functions to get the preferences.

• If no visible inspectors are defined, all inspectors (apart from Favorite and History List inspector) are visible.
• If no preferred inspector is defined, the first visible inspector will be used.

Fixed T27477

Test Plan: code review and application test

Reviewers: O1 MITK Reviewer Group I, kalali

Reviewed By: O1 MITK Reviewer Group I, kalali

Subscribers: kalali

Maniphest Tasks: T27477

Differential Revision: https://phabricator.mitk.org/D331