fix: don't set code for None epsg

[gadomski]

Related Issue(s):

• Closes Projection Extension migrate doesn't handle "proj:epsg": None case correctly #1543

PR Checklist:

• Pre-commit hooks pass (run pre-commit run --all-files)
• Tests pass (run pytest)
• This PR maintains or improves overall codebase code coverage.
• Changes are added to the CHANGELOG. See the docs for information about adding to the changelog.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 91.62%. Comparing base (4dc0e0f) to head (abc32fc).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1544      +/-   ##
==========================================
- Coverage   91.62%   91.62%   -0.01%     
==========================================
  Files          54       54              
  Lines        7580     7578       -2     
  Branches      923      923              
==========================================
- Hits         6945     6943       -2     
  Misses        451      451              
  Partials      184      184              

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[jsignell]

Thanks for taking this one! Just one suggestion.

[gadomski]

Agreed, I missed the delete, thanks.

[jsignell]

🚀