Refactor trial widget to not have nested links

The following discussion from !153166 (merged) should be addressed:

• @markrian started a discussion:

  issue (non-blocking): This link contains other links, which is not valid HTML.

  Since this was already the case before, I don't think it needs to block this MR, but it should probably be addressed in a follow-up.

  The behaviour here of making the entire element and popover clickable is probably intentional, since it makes it easy to click through to the discover page. Assuming that's correct, I'd suggest changing the DOM structure to avoid the nested links, and using something like a pseudo element to expand the clickable link area to fill the full element.

  For the popover, that's not feasible, since it contains three links 🤔

• Create a follow-up to do the same modification for duo pro trial widget