Slider component isn't accessible

- It doesn't have an `aria-valuenow` property, do we need to add this? As it will need to be updated with Javascript. Maybe we could add aria-hidden to the slider and allow screen reader users to just use the input field.
- We use `min` and `max` values but the [WCAG guidelines](https://www.w3.org/TR/wai-aria-practices-1.1/#slider_roles_states_props) suggest using `aria-valuemin` and `aria-valuemax` too.

Start with the slider component and its associated input field, then review the linked WCAG slider guidance. Check how the slider's value, minimum, and maximum are currently exposed and updated. Done means the component communicates the correct accessible values to screen readers without breaking input behavior.

Written by the indexing model from the issue text.