test(sidekick): enable codecov

[coryan]

Fixes #1543 - internal/sidekick is at 83.31% coverage. Most of the untested code is error handling.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83.31%. Comparing base (348290a) to head (9e45130).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1590      +/-   ##
==========================================
- Coverage   83.37%   83.31%   -0.06%     
==========================================
  Files          14       57      +43     
  Lines        1173     6235    +5062     
==========================================
+ Hits          978     5195    +4217     
- Misses        141      798     +657     
- Partials       54      242     +188     

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