[web-client] integrate the migrated theme in the github CI

- upgrade to ubuntu-24.04 to get NodeJS v20
- remove DEBUG (V=1) environment / in a ViteJS env the DEBUG environment is
  reserved for interactive debugging tasks (not for verbose build messages).

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

.github/workflows/integration.yml

@@ -44,19 +44,8 @@ jobs:
         with:
           python-version: '3.12'
           architecture: 'x64'
-      - name: Cache Python dependencies
-        id: cache-python
-        uses: actions/cache@v4
-        with:
-          path: |
-            ./local
-            ./.nvm
-            ./node_modules
-          key: python-ubuntu-24.04-3.12-${{ hashFiles('requirements*.txt', 'setup.py','.nvmrc', 'package.json') }}
-      - name: Install node dependencies
-        run: make V=1 node.env
       - name: Build themes
-        run: make V=1 themes.all
+        run: make themes.all
 
   documentation:
     name: Documentation