perf: 替换头像；修改导航栏气泡样式

src/layout/components/NavHeader/AccountDropdown.vue

@@ -39,7 +39,7 @@ export default {
   name: 'AccountDropdown',
   data() {
     return {
-      avatarUrl: require('@/assets/img/admin.png'),
+      avatarUrl: require('@/assets/img/head-portrait.png'),
       showApiKey: false
     }
   },

src/layout/components/NavHeader/index.vue

@@ -215,5 +215,12 @@ export default {
       display: none !important;;
     }
   }
+
+  >>> .el-badge__content {
+    color: var(--color-primary);
+  }
+  >>> .el-badge__content--primary {
+    background-color: #fff;
+  }
 </style>