Do not hide child nodes

Summary:
Add new node if parent node is part of the selection

This will select newly created child nodes such as segmentation or surfaces
to a render window if the parent node was already part of the selection.

Test Plan:
manual testing

• open MITK, load an image
• close the Standard Display, open the MxN Display
• uncheck the "Data -> Select all nodes" checkbox
• open the Segmentation view, create a new segmentation node
• draw in the render window
• check the selected nodes in "Data" and see that the segmentation node is available

Reviewers: s434n, O3 MITK Reviewer Group II

Reviewed By: s434n, O3 MITK Reviewer Group II

Subscribers: s434n, kalali

Maniphest Tasks: T29533

Differential Revision: https://phabricator.mitk.org/D800