Improve CI log readability by removing sccache debug statements

[jnbooth]

This gets rid of all those messages like

warning: [email protected]: [2025-07-19T16:17:37Z DEBUG sccache::config] Attempting to read config file at "/home/runner/.config/sccache/config"

that make it incredibly difficult to spot why tests fail.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (c6710b7) to head (17a89b6).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #1315   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           75        75           
  Lines        12772     12772           
=========================================
  Hits         12772     12772           

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[LeonMatthesKDAB]

Approved, We can always add it back when needed.