[CI] Attempt to fix sporadic ccache key restore failure on Windows

[aobolensk]

Failure examples:

• https://github.com/learning-process/parallel_programming_course/actions/runs/27092193157/job/79958099680?pr=804
• https://github.com/learning-process/parallel_programming_course/actions/runs/27094992419/job/79965554625?pr=806

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.00%. Comparing base (e7dc076) to head (e69a488).

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #807   +/-   ##
=======================================
  Coverage   92.00%   92.00%           
=======================================
  Files          14       14           
  Lines         463      463           
  Branches      169      171    +2     
=======================================
  Hits          426      426           
  Misses          5        5           
  Partials       32       32           

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.