chore: prefer named exports (#8315)

* chore: prefer named exports

* chore: fix import

src/picker/test/cascade.legacy.js

@@ -1,4 +1,4 @@
-import Picker from '..';
+import { Picker } from '..';
 import { mount, triggerDrag } from '../../../test';
 
 const COLUMNS = [

src/picker/test/index.spec.tsx

@@ -1,6 +1,6 @@
-import Picker from '..';
-import PickerColumn from '../PickerColumn';
 import { later, mount, triggerDrag } from '../../../test';
+import { Picker } from '..';
+import PickerColumn from '../PickerColumn';
 
 const simpleColumn = ['1990', '1991', '1992', '1993', '1994', '1995'];
 const columns = [