Suggested actions to become a composite component with a single TAB to go in/out

[compulim]

Feature Request

While we are working on navigable transcript, aria-activedescendant really shines.

We should also move suggested actions to use the aria-activedescendant or roving tab index to make things easier to select thru TAB keys.

The whole suggested actions container should be a single TAB. And for buttons inside, they should not need to be tabbable, but interactable using arrow keys. Similar to how auto-completion box is done.

[feature-request]