Meghan Markle’s American Riviera Orchard is poised to become a “slow-burning hit,” by year’s end, according to a Hollywood insider. This led PR expert Mayah Riaz to focus on Meghan’s new line of strawberry jam, which is benefitting from a slow and mysterious ad campaign. “So far, the jams have been sent to only 50 people,” she said. “This suggests that it will be an exclusive and limited edition item.” “It has already been reported a single jam jar could cost three figures,” she added. “I believe that is entirely likely from what we have seen so far. This is not rare for a celebrity brand. The…