I’m worn out,” a disembodied male voice announced from the darkness as the credits rolled following a screening of “Mission: Impossible — Fallout.”This declaration was met with appreciative laughter in the packed summer theater.What with all the lightning storm skydiving, martial arts pugilism, rooftop vaulting, cliff scaling, car chases, motorcycle crashes, helicopter dogfights and all-around Usain Bolting, who could blame the guy for being exhausted?“Fallout” is the sixth movie …