After two period pictures, the venerable English director Mike Leigh returns to contemporary London with his acute new film “Hard Truths.” In the post-Covid present day, its story examines how pain, depression, anger, and isolation affect a middle-aged British Afro-Caribbean woman and her family. A bit of a comedy but more of a drama, the movie is filled with uncomfortable moments and a wholly compelling, even riveting, exploration of mental and social deterioration.