[Feature Request] The Cascader selector should reset the activePath and menus of the panel when it is cleared.

### Existing Component
是

### Component Name
Cascader

### Description
可清空的级联选择器，选择某一项清空，再次打开面板时，面板的路径样式为激活状态且面板全部展开

文件：cascader.vue

handleClear() {
this.presentText = '';
this.inputValue = '';
this.panel.activePath = [];
this.panel.menus = this.panel.menus.slice(0, 1);
this.panel.clearCheckedNodes();
},