[Accessibility] Set focus to first element in card for Action.ShowCard
Related Issue
Fixes #7689
Description
When the user show's a card, the focus remains on the ShowCard action instead of moving to the first focusable element in the now visible card.
Fixed by recursively searching for the first focusable element (input or action) within the card and focusing on it.
How Verified
Verified manually on the adaptivecards-site.
Outstanding Issue
How do we want this to behave with other actions? For example, if we have two actions (ShowCard and OpenUrl) in that order, selecting show card will focus on an element within the card, and OpenUrl will never have focus.

Microsoft Reviewers: Open in CodeFlow
Hi @anna-dingler. Thanks for helping make the AdaptiveCards JS renderer + tooling better. As additional verification, once the JS build succeeds, please go to the test site to test out your website/designer changes.
Hi @anna-dingler. This pull request has had no recent activity for the past 5 days . Please take the necessary actions (review, address feedback or commit if reviewed already) to move this along.
Staleness reset by anna-dingler
Hi @anna-dingler. This pull request has had no recent activity for the past 5 days . Please take the necessary actions (review, address feedback or commit if reviewed already) to move this along.
Closing this PR since the original bug was closed.
Staleness reset by anna-dingler