paper-badge has a tabindex while it shouldn't because of role=status

[erikkroes]

Description

paper-badge has role="status" and a tabindex="0".

Expected outcome

According to the wai-aria specs, a component with role="status" should not receive focus.

Actual outcome

paper-badge has tabindex="0" and can receive keyboard focus (although it is not even visible).

Live Demo

https://www.webcomponents.org/element/PolymerElements/paper-badge/demo/demo/index.html

Steps to reproduce

1. Create a page with paper-badge
2. Open the page in a web browser
3. Navigate with the TAB-key
4. paper-badge receives focus