Avoid duplicate artifact

The bumped `actions/upload-artifact@v4` correctly found a conflicting upload.
The test-reports for 4 Jira versions were overwriting each other.
Anyway, we don't need them because `gradle-build-action` publishes Gradle scans.

.github/workflows/ci.yml

@@ -28,12 +28,6 @@ jobs:
       with:
         gradle-version: wrapper
         arguments: build
-    - name: Upload test reports
-      if: always()
-      uses: actions/upload-artifact@v4
-      with:
-        name: test-reports
-        path: build/reports/tests
     - name: Upload diagnoses
       if: always()
       uses: actions/upload-artifact@v4