Here’s a guest-star alert worth mentioning, on a show that usually isn’t: Charlie Sheen, as a therapist, gets a new patient: Lindsay Lohan, playing an off-kilter version of herself. If that’s not redundant. When Lohan teared up the other day on Late Show with David Letterman, responding to some words of support from her host, that was a good career move. Whether this appearance, which has her hawking some product for a Japanese TV ad, continues that positive momentum, or negate