chore: prefer named exports (#8315)

* chore: prefer named exports

* chore: fix import

src/popover/Popover.tsx

@@ -18,8 +18,8 @@ import { BORDER_BOTTOM } from '../utils/constant';
 import { useClickAway } from '@vant/use';
 
 // Components
-import Icon from '../icon';
-import Popup from '../popup';
+import { Icon } from '../icon';
+import { Popup } from '../popup';
 
 const [name, bem] = createNamespace('popover');
 

src/popover/demo/index.vue

@@ -122,7 +122,7 @@
 <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/popover/test/index.spec.tsx

@@ -1,4 +1,4 @@
-import Popover from '..';
+import { Popover } from '..';
 import { later, mount, trigger } from '../../../test';
 
 const baseActions = [