"Add the extension" button on "Get Extension" page requires clicking on text

[rhelmer]

Looks like a similar issue as #439, on the dedicated interstitial "Get Extension" page:

https://members.rally.mozilla.org/get-extension

Hovering over the text underlines and it now works:

Clicking anywhere on the button outside of the text "Add the Extension" does nothing:

[Carla-Moz]

Actually, the text shouldn't underline on hover based on Casey's designs