Accessibility — elements with no focus style in ACP and Prosilver

Some elements in ACP and Prosilver styles have CSS that cancels the default focus style by setting `outline: none` but provides no alternative styling to show they're focused. As a result, focused and non-focused states look identical.

For example: Day/Month/Year fields under "Birthday" in UCP (navigate via keyboard using `Tab` key to reproduce).

See:

https://www.a11yproject.com/posts/never-remove-css-outlines/

https://webaim.org/blog/plague-of-outline-0/

https://www.outlinenone.com/

https://betterprogramming.pub/a11y-never-remove-the-outlines-ee4efc7a9968?gi=5955f3df65d9