[WC-2942]: Fix carousel focus indicator

[HedwigAR]

Pull request type

Bug fix (non-breaking change which fixes an issue)

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Description

Added focus indicators to the navigation buttons in the carousel, disabled autoplay by default since it's not accessible.

What should be covered while testing?

• Autoplay should be disabled in settings by default,
• When tabbing to the navigation buttons on the carousel (the left and right arrows) a focus indicator should appear. The focus indicator should be blue and with a 2px offset, to match our other focus indicators.
• The navigation buttons should also have a default white semi transparent circular background to make them stand out more.