fix: fixing button groups on the mobile version

data/upgrade.html

@@ -37,7 +37,7 @@
             <input type="file" name="settings" id="restore-file" accept=".json">
           </label>
 
-          <div role="group">
+          <div class="grid">
             <button type="submit">Restore</button>
             <button type="button" class="secondary" onclick="window.location='/api/backup/save';">Backup</button>
           </div>