ATLANTA — Don Mattingly remained steadfast that the Atlanta Braves, despite their sub-.500 record two weeks into the season, are still the team to beat in the National League East as his Miami Marlins made their way into Truist Park this weekend. “The last time I looked, they’re the ones that won that championship last year,” the manager said Friday prior to the series opener. “Until they haven’t, they’re the champs. They’re still the bar our division looks at. Nobody’s going to look at 12 games or however many they played and say the Braves aren’t part of this. For sure, they’re that team.” W…