Fix coverage CI: use ubuntu-24.04 for lcov 2.x support

The --ignore-errors mismatch and --ignore-errors unused flags
require lcov 2.x, which is not available on ubuntu-22.04.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: facontidavide

.github/workflows/cmake_ubuntu.yml

@@ -47,7 +47,7 @@ jobs:
       run: ctest --test-dir build/${{env.BUILD_TYPE}}
 
   coverage:
-    runs-on: ubuntu-22.04
+    runs-on: ubuntu-24.04
 
     steps:
     - uses: actions/checkout@v6