Add focus state for Back-to-Top link.

[richardgaunt]

User story

As a developer I want to be able to add focus state to the back to top button So that override styles

Description

UIKit already had a focus state, but it was set to transparent as per designs - the design does not have a focus state.

We need to add a focus state to uikit so it can be overridden

Acceptance criteria

Given I am a developer When I override back to top component styles Then I expect to be able to change a variable to change the focus state

[sonamchaturvedi28]

Test Env: DEV Test Status: PASS Test Result:

• Focus state is added to the back to top button