消息弹出组件样式类名调整

src/components/app-message-popover/app-message-popover.less

-.item {
+.app-message-popover {
   height: 24px;
   line-height: 24px;
   padding: 0 5px 0 0;

src/components/app-message-popover/app-message-popover.vue

 <template>
     <!-- 消息弹出框绘制开始 -->
-    <el-badge :is-dot="showIsDot" class="item">
+    <el-badge :is-dot="showIsDot" class="app-message-popover">
         <el-popover
                 placement="bottom"
                 trigger="click"