CI: unblock Code Analysers job by migrating deprecated artifact action

[Copilot]

The Code Analysers matrix job (-fsanitize=undefined -static-libubsan) was failing before analysis execution due to a deprecated GitHub Action (actions/upload-artifact@v3) now hard-blocked by GitHub. This change updates that failing path to the supported action version.

• Root cause

  • The analyser job’s failure-handler step used actions/upload-artifact@v3, which is rejected at runtime by GitHub Actions.

• Targeted workflow change

  • Updated only the analyser job artifact upload step in .github/workflows/tests.yml:
    • actions/upload-artifact@v3 → actions/upload-artifact@v4
  • No changes to analyzer flags, build commands, or test logic.

• Scope

  • Surgical CI workflow fix focused on the failing job path (analyse job, failure artifact upload step).

- if: ${{ failure() }}
  name: Upload tests output
  uses: actions/upload-artifact@v4
  with:
    name: "analysis${{ matrix.flags }}"
    path: tests