[EuiSearchBar/EuiSearchBarFilters] Allow exclusions in select value filter

**Problem Statement**

`EuiSearchBar/EuiSearchBarFilters` components do not support allowing exclusion for `FieldValueSelectionFilter`.

**Proposed Solution**

Add `allowExclusions` prop to `FieldValueSelectionFilterConfigType` so it can be passed to `EuiSelectable` used in `FieldValueSelectionFilter` component.

**Use Case**

When working on https://github.com/elastic/kibana/pull/229698 it was discovered that user cannot easily filter out the misconfigured repository and needs to either use the specific query in the search bar or needs to filter each repository individually to see all the snapshots.

**Value / Impact**

This improvement would allow users to filter out misconfigured repository easily.

**Urgency**

It's not a blocker but would certainly improve UX. Unfortunately there are no workarounds.