Treenav: navigating via keyboard updates active page highlight but does not navigate to the selected page

[matthewgallo]

Detailed description

Describe in detail the issue you’re having.

When using the treenav via keyboard and selecting a page, the active tab highlight is applied but the page does not change to the page that was selected.

What did you expect to happen? What happened instead? What would you like to see changed?

I expected the page to navigate to the page that was selected.

What browser are you working in?

Chrome

Steps to reproduce the issue

1. Go to https://gatsby.carbondesignsystem.com/getting-started/
2. Attempt to change page via keyboard within the treenav
3. You can see now that the active highlight was changed but the page did not change