ci(ref_imgs): make the CI fail if there not all ref. images are added (#7086)

.github/workflows/ccpp.yml

@@ -91,9 +91,34 @@ jobs:
         path: |
              tests/ref_imgs*/**/*_err.png
              test_screenshot_error.h
-#    - name: Upload coverage to Codecov
-#      uses: codecov/codecov-action@v4
-#      if: github.event_name == 'push' && github.repository == 'lvgl/lvgl'
-#      with:
-#        fail_ci_if_error: true
-#        verbose: true
+    - id: check_untracked_ref_imgs
+      name: Check for new files and upload them as artifacts if found
+      run: |
+        NEW_REF_IMGS=$(git status --porcelain -- tests/ref_imgs* | grep '^??' | awk '{print $2}')
+
+        if [ -n "$NEW_REF_IMGS" ]; then
+          echo "New files were added during the build process."
+          echo "Uploading untracked ref. images as artifacts..."
+          for file in $NEW_REF_IMGS; do
+            echo "Found new file: $file"
+          done
+          zip -r untracked_ref_imgs.zip $NEW_REF_IMGS
+          echo "::set-output name=new_ref_imgs_found::true"
+        else
+          echo "No new files were found."
+          echo "::set-output name=new_ref_imgs_found::false"
+        fi
+
+    - name: Upload untracked reference images
+      if: steps.check_untracked_ref_imgs.outputs.new_ref_imgs_found == 'true'
+      uses: actions/upload-artifact@v3
+      with:
+        name: Untracked Reference Images
+        path: untracked_ref_imgs.zip
+
+    - name: Fail the build if new files were found
+      if: steps.check_untracked_ref_imgs.outputs.new_ref_imgs_found == 'true'
+      run: |
+        echo "Failing the build due to newly generated reference images."
+        exit 1
+