fix for a bug in edge_drawing.py

[sturkmen72]

Pull Request Readiness Checklist

See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request

• I agree to contribute to the project under Apache 2 License.
• To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV
• The PR is proposed to the proper branch
• There is a reference to the original bug report and related work
• There is accuracy test, performance test and test data in opencv_extra repository, if applicable
  Patch to opencv_extra has the same branch name.
• The feature is well documented and sample code can be built with the project CMake

[sturkmen72]

you can see sample result images
before fix
https://raw.githubusercontent.com/PacktPublishing/Learning-OpenCV-5-Computer-Vision-with-Python-Fourth-Edition/1c1b539496416c367b0dd4d73a65188401336667/chapter03/planets_edge_drawing_ellipses.jpg
after fix
https://raw.githubusercontent.com/PacktPublishing/Learning-OpenCV-5-Computer-Vision-with-Python-Fourth-Edition/edd4f4cf893c57c92e4be849aa51e187c40d8452/chapter03/planets_edge_drawing_ellipses.jpg

(note : output images are from other very similar code)