fix: add border radius to lens cmp wrapping cards

[derHowie]

Fixes BX-1609

What changed (plus any additional context for devs)

Passed border radius from <Card /> props to <Lens /> to fix navigation highlighting display issues and also removed a few things from the tab index that probably don't need to be there.

This screen could probably use some extra kb functionality + nav, but this PR just fixes the existing display issues.

Screen recordings / screenshots

What to test

Make sure that selecting the Last Week's Earnings card with the keyboard looks and behaves normally.