chore: prefer named exports (#8315)

* chore: prefer named exports

* chore: fix import

src/cascader/Cascader.tsx

@@ -2,9 +2,9 @@ import { nextTick, PropType, reactive, watch, defineComponent } from 'vue';
 import { createNamespace } from '../utils';
 
 // Components
-import Tab from '../tab';
-import Tabs from '../tabs';
-import Icon from '../icon';
+import { Tab } from '../tab';
+import { Tabs } from '../tabs';
+import { Icon } from '../icon';
 
 const [name, bem, t] = createNamespace('cascader');
 

src/cascader/test/index.spec.ts

@@ -1,6 +1,5 @@
-import Cascader from '..';
+import { Cascader } from '..';
 import { mount, later } from '../../../test';
-
 import options from '../demo/area-en-US';
 
 test('should emit change event when active option changed', async () => {