[BUG] Implementation of plotinstanceborder missing for polyellipse

[pvogt09]

In raising this issue, I confirm the following:

• I have read and understood the contributors guide.
• The issue I am reporting can be replicated.
• The issue I am reporting isn't a duplicate (see closed issues, and open issues).

Description
The predefined pole areas

• PolyEllipse and
• PolyEllipsesquare

lack an implementation of the method plotinstanceborder defined in GammaArea.

Steps to Reproduce
None.

How familiar are you with the the source code relevant to this issue?:

10

Expected behavior
Implementation should be present.

Environment (please complete the following information):

• Matlab Version: all

Troubleshooting Undertaken, and/or Additional Context
None.