feat(Cascader): add option slot (#9036)

* feat(Cascader): add option-text slot

* chore: adjust slot

src/cascader/test/__snapshots__/index.spec.ts.snap

@@ -5,6 +5,12 @@ exports[`should change close icon when using close-icon prop 1`] = `
 </i>
 `;
 
+exports[`should render option slot correctly 1`] = `
+<li class="van-cascader__option">
+  Custom Option foo
+</li>
+`;
+
 exports[`should render title slot correctly 1`] = `
 <h2 class="van-cascader__title">
   Custom Title

src/cascader/test/index.spec.ts

@@ -88,6 +88,20 @@ test('should render title slot correctly', () => {
   expect(wrapper.find('.van-cascader__title').html()).toMatchSnapshot();
 });
 
+test('should render option slot correctly', async () => {
+  const option = { value: '1', text: 'foo' };
+  const wrapper = mount(Cascader, {
+    props: {
+      options: [option],
+    },
+    slots: {
+      option: ({ option }) => `Custom Option ${option.text}`,
+    },
+  });
+  await later();
+  expect(wrapper.find('.van-cascader__option').html()).toMatchSnapshot();
+});
+
 // TODO
 // test('should select correct option when value changed', async () => {
 //   const wrapper = mount(Cascader, {