Remove unused python content from planning interface directory

[sjahr]

Description

☝️

Checklist

• Required by CI: Code is auto formatted using clang-format
• Extend the tutorials / documentation reference
• Document API changes relevant to the user in the MIGRATION.md notes
• Create tests, which fail without this PR reference
• Include a screenshot if changing a GUI
• While waiting for someone to review your request, please help review another open pull request to support the maintainers

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (a8cc279) 51.15% compared to head (b4b32fe) 50.74%.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2665      +/-   ##
==========================================
- Coverage   51.15%   50.74%   -0.41%     
==========================================
  Files         393      392       -1     
  Lines       32753    32553     -200     
==========================================
- Hits        16753    16517     -236     
- Misses      16000    16036      +36     

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