fix(icon-workflow): succeed if no icons changed (#1805)

Relates to #939

To not fail icon import workflow/pipeline when nothing changed, see
[this successful workflow
run](https://github.com/SchwarzIT/onyx/actions/runs/10593460712)

.github/workflows/import-figma-icons.yml

@@ -38,10 +38,15 @@ jobs:
 
       - name: Generate changeset
         run: |
-          git add src/assets
+          git add .
           pnpm run generate:changeset
         working-directory: packages/icons
 
+      # needed to prevent creating empty PR when nothing but the formatting changed
+      - name: Format with prettier
+        run: pnpm prettier --write src/metadata.json
+        working-directory: packages/icons
+
       - name: Create pull request
         uses: peter-evans/create-pull-request@v6
         with: