After a few weeks off for the holiday and to find a bigger kitchen prep location to accomodate its burgeoning popularity, Mission Street Food returns this Thursday with a guest chef (Tia Harrison of Sociale/Avedano's Holly Park Market) and a menu theme "inspired by butter, hip-hop and gentrification: 'The Dirty South Cleans Up Pretty Good.'" As before, it will take place at Lung Shan (2234 Mission at 19th St.) from 6 p.m. to midnight; check out this week's full menu (smoked duck beignets!) on t