Pamela Adlon at her office in Beverly Hills. “That’s just my mentality: Nothing is ever promised.” Life is a fly-by-the-seat-of-your pants odyssey with Adlon, a former child actor whose credits include “The Facts of Life,” “Grease 2” and “Californication.” Her L.A. office is filled with remnants of “Better Things,” which premiered in 2017: artwork from Sam’s busy household hangs on …