Selected value for Single/MultiList

Currently, the selected value from Single/MultiList is returned as a string or an array of strings in props like onValueChange(..) and beforeValueChange(..). Hence, in the current case, we miss out on the `doc_count` of the selected values.

To enable consistency across all the components, we should return the selected value as an object or an array of objects, where the shape of object is:

```
{
label: ,
count:
}
```