Actors Kerry Washington and Martin Sheen have delivered rousing speeches celebrating labor unity at a rally for striking Hollywood actors and writers and other workers supporting them. Washington, star of the series “Scandal,” told the crowd gathered Tuesday outside Disney Studios in Burbank, California that “we are here because we know that unions matter.” The former president on “The West Wing” Sheen emphasized that the toll being taken as the two strikes stretch out only shows that the fight is worth it. Actors have been on strike for more than a month, writers for more than three months.