“Search Party” started as the story of a search for a missing girl who never really wanted to be found. Everything that’s happened since that series premiere has been a repercussion of a decision to look for someone who no one seemed to care was missing. At its best, the fourth season of the show serves as something of a mirror image of that inciting incident in that the searcher has become a missing girl herself. Will anyone try to find Dory Sief? And will she too eventually not want to be discovered?