fix(build): ensure opencv-contrib modules path is set correctly

[rainyl]

fixes: #423

When building OpenCV from source with contrib modules, the OPENCV_EXTRA_MODULES_PATH variable was not being forced, causing builds to ignore changes to the included modules list. This adds the FORCE flag to the cache setting, ensuring the correct modules are built when the configuration changes.

[codecov-commenter]

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Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.76%. Comparing base (4d0cda0) to head (78a0331).
⚠️ Report is 1 commits behind head on main.
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Additional details and impacted files

@@           Coverage Diff           @@
##             main     #426   +/-   ##
=======================================
  Coverage   92.76%   92.76%           
=======================================
  Files          56       56           
  Lines       11442    11442           
=======================================
  Hits        10614    10614           
  Misses        828      828           

Flag	Coverage Δ
unittests	92.76% <ø> (ø)

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