On a sticky August night at a restaurant near the Kaufman Astoria Studios in Queens, N.Y., the reunited cast, writers and staff of CBS’s Murphy Brown, including Candice Bergen, are gathered for a drink and some food after a taping of the reboot of the iconic 1990s newsroom comedy. The series hasn’t premiered yet, and there’s a kind of wobbly joy in the room. Most of the characters are familiar.