Ensure proper accessible labeling logic for Multiselect

There has been development difficulty in properly assigning aria-label and aria-labelledby to MultiSelect - see https://github.com/folio-org/stripes-smart-components/pull/1216 - Axe complains about missing roles on elements, and it's apparent that the `aria-label` prop alone doesn't seem to apply its values to the elements. 

As a resource, examples of patterns like labeling a MultiSelect via an Accordion's label should be created in storybook.