Avoiding more numpy 2.0 deprecation warnings

[eepeterson]

Description

Numpy 2.0 deprecates np.cross for 2D arrays which was used in the Polygon class. To address this we simply append a 0 to the points for the dimension perpendicular to the plane and take the only non-zero component of the cross product which is that last dimension.

Fixes # (issue)

Checklist

• I have performed a self-review of my own code
• I have run clang-format (version 15) on any C++ source files (if applicable)
• I have followed the style guidelines for Python source files (if applicable)
• I have made corresponding changes to the documentation (if applicable)
• I have added tests that prove my fix is effective or that my feature works (if applicable)