Do not hide helper nodes

Summary:
Do not process new incoming helpler nodes

The changes will also stop changing the visibility
for render windows that do not have "Select all nodes" checkbox
unchecked.
This leads to all helper nodes always being visible.

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
• see how the feedback contour is drawn

Reviewers: s434n, O3 MITK Reviewer Group II

Reviewed By: s434n, O3 MITK Reviewer Group II

Subscribers: kalali, s434n

Maniphest Tasks: T29534

Differential Revision: https://phabricator.mitk.org/D799