Jessica Biel in a teacup-rattling ’20s period piece? With her lewd pinup grin and husky flat voice, she sticks out like a sore starlet in Easy Virtue — but that’s the whole point in this loosely ”freshened up” version of a Noël Coward play. Biel plays the race-car-driving American bride of ?a British rich kid (Ben Barnes), who takes her to the family mansion. Once there, she squares off against her new ?in-laws — Kristin Scott Thomas as Barnes’ embattled mother, Colin Firth as the whipped-puppy patriarch — with vulgar vitality, even if the picture itself is only mechanically breezy. B?