To reset the controller value to null.
The second param is optional which can be used to define the reset
value (default is `null).
For example,
clearValue("searchbox", "")
To clear the values
An optional param can be defined to reset values for controllers.
For example,
clearValues({ "searchbox": "", "author-filter": [] })
A map of search controller id to SearchController
One can loop through the map to get the corresponding raw value for each filter.
For example,
selectedValues.forEach((filterId, filterValue){
// do something with extracted values
})