fix(Stepper): 修复 blur 事件触发异常 (#8620)

* fix(Stepper): 修复blur事件触发异常

* Update index.spec.ts

src/stepper/test/index.spec.ts

@@ -1,3 +1,4 @@
+import { nextTick } from 'vue';
 import { Stepper } from '..';
 import { mount, later } from '../../../test';
 
@@ -244,6 +245,7 @@ test('should format input value when stepper blured', async () => {
 
   await input.trigger('blur');
   expect(wrapper.emitted('update:modelValue')![1]).toEqual([3]);
+  await nextTick();
   expect(wrapper.emitted('blur')).toBeTruthy();
 });