remove deprecated mode keyword from build_client and add --cleanup

.github/workflows/publish-pypi.yml

@@ -31,7 +31,7 @@ jobs:
     - name: build refl1d webview
       run: |
         python -m pip install -e ./refl1d
-        python -m refl1d.webview.build_client --mode=production
+        python -m refl1d.webview.build_client --cleanup
 
     - name: Install dependencies for building the wheel
       run: |