feat(dropdown-item): add root-portal prop support (#5256)

Co-authored-by: liuhaihonggia <liuhaihong@youzan.com>

packages/dropdown-item/index.ts

@@ -34,6 +34,10 @@ VantComponent({
       type: Boolean,
       value: false,
     },
+    rootPortal: {
+      type: Boolean,
+      value: false,
+    },
   },
 
   data: {

packages/dropdown-item/index.wxml

@@ -13,6 +13,7 @@
     position="{{ direction === 'down' ? 'top' : 'bottom' }}"
     duration="{{ transition ? duration : 0 }}"
     close-on-click-overlay="{{ closeOnClickOverlay }}"
+    rootPortal="{{ rootPortal }}"
     bind:enter="onOpen"
     bind:leave="onClose"
     bind:close="toggle"

packages/dropdown-menu/README.md

@@ -196,6 +196,7 @@ Page({
 | title-class | 标题额外类名，建议使用自定义样式 item-title-class 代替 | _string_ | - |
 | popup-style | 自定义弹出层样式 | _string_ | - |
 | use-before-toggle `v1.10.12` | 是否开启下拉菜单打开或者关闭前校验  | _boolean_ | `false` |
+| root-portal `v1.10.14` | 是否从页面子树中脱离出来，用于解决各种 fixed 失效问题，微信基础库 >= `2.25.2 `  | _boolean_ | `false` |
 
 ### DropdownItem Events