chore: prefer named exports (#8315)

* chore: prefer named exports

* chore: fix import

src/tab/Tab.tsx

@@ -16,7 +16,7 @@ import { useParent } from '@vant/use';
 import { routeProps } from '../composables/use-route';
 
 // Components
-import SwipeItem from '../swipe-item';
+import { SwipeItem } from '../swipe-item';
 
 const [name, bem] = createNamespace('tab');
 

src/tab/demo/index.vue

@@ -105,7 +105,7 @@
 <script lang="ts">
 import { reactive, toRefs } from 'vue';
 import { useTranslate } from '@demo/use-translate';
-import Toast from '../../toast';
+import { Toast } from '../../toast';
 
 const i18n = {
   'zh-CN': {

src/tab/test/index.legacy.js

@@ -1,4 +1,4 @@
-import Tabs from '../../tabs';
+import { Tabs } from '../../tabs';
 import { mount, later, triggerDrag, mockScrollTop } from '../../../test';
 
 function createWrapper(options = {}) {

src/tab/test/insert.spec.js

@@ -1,6 +1,6 @@
 import { mount, later } from '../../../test';
-import Tab from '..';
-import Tabs from '../../tabs';
+import { Tab } from '..';
+import { Tabs } from '../../tabs';
 
 test('should render correctly after inserting a tab', async () => {
   const wrapper = mount({