refactor(layout): improve sidebar structure and icon consistency

- Streamlined the sidebar component in `index.vue` by consolidating class bindings and removing unnecessary line breaks for better readability.
- Updated icon references for LSS and LiveStream management to use `pixelarticons` for improved visual consistency across the application.

src/layout/index.vue

@@ -219,13 +219,13 @@ const menuItems: MenuItem[] = [
     path: '/lss-manage',
     title: 'LSS 管理',
     icon: 'mdi:connection',
-    children: [{ path: '/lss-manage/list', title: 'LSS 列表', icon: 'mdi:list-box' }]
+    children: [{ path: '/lss-manage/list', title: 'LSS 列表', icon: 'pixelarticons:list' }]
   },
   {
     path: '/live-stream-manage',
     title: 'LiveStream 管理',
     icon: 'mdi:video-wireless',
-    children: [{ path: '/live-stream-manage/list', title: 'LiveStream 列表', icon: 'mdi:list-box ' }]
+    children: [{ path: '/live-stream-manage/list', title: 'LiveStream 列表', icon: 'pixelarticons:list' }]
   },
   { path: '/cc', title: 'Cloudflare Stream', icon: 'mdi:cloud' },
   { path: '/camera-vendor', title: '摄像头配置', icon: 'mdi:cctv' },