On the (mobile) NYTimes home page it's the 24th story down, and entitled "Officer Attacked During Capitol Riot Died of Multiple Strokes" and redirects to https://www.nytimes.com/live/2021/04/19/us/joe-biden-news/ - some sort of political live feed? The Sicknick story is the 6th down in this feed, buried a couple thousand words in. Not exactly the clear and unambiguous retraction I'd expect from a serious newspaper.