Filter: Announce number of filters applied when Filter button is focused

[marvieqa]

Description

When a filter is applied, we display the number filters applied beside the label. When using a screen reader, this value is not announced at all, leaving users unsure whether they have applied a filter or not. We should announce this information.

Acceptance Criteria

• [ ] Announce the number of filters applied when Filter is in focus.
  • [ ] Explore using an <aria-label=" Filter, 3 Filters applied">