Few things are more satisfying in the arts than unjustly forgotten figures at last accorded a rightful place in the canon. Then there are the perennially celebrated artists who are so important that they must be presented anew to each successive generation, a daunting task for museums, especially encyclopedic ones that are expected to revisit the major masters over and over again while finding fresh reasons for their relevance. Yet the Museum of Modern Art’s exhibition “Frank Lloyd Wright at 150: Unpacking the Archive” was a more hazardous proposition than its universally beloved subject might indicate.