ci: remove codecov token

[paul58914080]

Checklist for self review:

• My code follows the contribution guidelines of this project
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• My commits follow conventional commit message guidelines

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 88.17%. Comparing base (83dfcd7) to head (0677a1f).
⚠️ Report is 82 commits behind head on main.

Additional details and impacted files

@@             Coverage Diff              @@
##               main     #569      +/-   ##
============================================
+ Coverage     87.69%   88.17%   +0.48%     
- Complexity      188      204      +16     
============================================
  Files            51       51              
  Lines           520      516       -4     
  Branches         21       21              
============================================
- Hits            456      455       -1     
+ Misses           53       50       -3     
  Partials         11       11              

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