Vertical section navigation active element is a header that behaves like a link

[rmccar]

**Summary
The active page element on the vertical variant of the section navigation component is a header that seems to behave like a link when hovered over with an underline. This needs to be changed so that it is no longer a header, it should be a link like the links to other pages. This will provide a more consistent experience for users as it will behave like the links for other pages.

Expected behaviour
The active page element on the section navigation component should behave like the links to the other pages, should be able to be clicked, focused and when hovered over adds a underline.
See comments from @Majsol

Actual behaviour
The vertical section navigation headers have an underline added when hovered as if they are a link when they aren't and aren't clickable or focusable. As can be seen here on the "section 6" item header.

Screenshots/Examples**

[Majsol]

Richard and I had a chat about this ticket. We have decided to change the functionality of the section header so it behaves like a link even when it is already selected.