She’s earned a notorious reputation for being one of Hollywood’s most difficult actresses to work with – and now Katherine Heigl won’t play nice with Duane Reade either. The gorgeous, but grumpy, “Grey’s Anatomy” star slapped the pharmacy giant with a $6 million-plus lawsuit Wednesday alleging she was photographed without consent by paparazzi outside one of its Manhattan stores — and that Duane Reade then brazenly misused the image for its own advertising