fix: always show attention devices card

internal/web/ui/templates/dashboard.html

@@ -26,7 +26,6 @@
   <div class="stat"><div class="k">执行中任务</div><div class="v">{{.RunningTaskCount}}</div><div class="hint">正在下发或控制节点</div></div>
 </div>
 
-{{if .AttentionDevices}}
 <div class="card">
   <h2>异常设备</h2>
   <div class="table-wrap" style="margin-top:10px">
@@ -48,7 +47,6 @@
     </table>
   </div>
 </div>
-{{end}}
 
 <div class="card">
   <h2>最近任务</h2>