MultiDropdownList and MultiList should allow users to unselect/clear selected value(s) even if no results are found

**Issue Type:**
enhancement

**Platform:**
Web

**Description:**
`MultiDropdownList` and `MultiList` should allow users to unselect/clear selected value(s) even if no results are found without using `SelectedFilter`

**Minimal reproduction of the problem with instructions:**
Assume you have a `Datasearch` and a `MultiList` and that we don't use the `SelectedFilter` component but only a `ClearAll` button to reset all criteria.
The values displayed in the `MultiList` are refreshed based upon new keywords typed in the `Datasearch` with the following config:
```

```
If the user select a value, and then type keywords in the `Datasearch` with no results for the selected value and keyword combination, then the list of options is empty but the previously selected value is still there, but the user can't unselect it.
The selected option(s) should still be displayed so he can unselect them, or at least there should be a inline clear icon to reset the component selection itself

**Reactivesearch version:** 2.12.0

**Browser:** all