WASHINGTON — After more than 30 hours of hearings, the Senate is on track to confirm Ketanji Brown Jackson as the first Black woman on the Supreme Court. But Democrats seem unlikely to confirm her with a robust bipartisan vote, dashing President Joe Biden’s hopes for a grand reset after partisan battles over other high court nominees.Democratic Sen. Joe Manchin announced Friday that he plans to vote for her, likely assuring the confirmation.Manchin was a key vote to watch because he has bucked his party on some …