ComboBox and AutoComplete don't have a value slot functionality

The Native ComboBox and AutoComplete do not support the [valueRender](https://www.telerik.com/kendo-vue-ui/components/dropdowns/api/DropDownListProps/#toc-valuerender) prop. Thus the selected value cannot have a custom rendering. 

**The valueRender prop is available in the DropDownList.**
https://www.telerik.com/kendo-vue-ui/components/dropdowns/dropdownlist/custom-rendering/#toc-values