DETROIT — Stanley Johnson has spent nearly the entire summer in his home state of California. Instead of enjoying the pleasant weather and palm trees, Johnson has spent the bulk of his time working on his basketball skills in a Newport Beach gym. It has been 10 years since the Detroit Pistons selected Johnson as the No. 8 overall pick in the 2015 NBA Draft. He joined the Pistons as a 19-year-old prospect who rose to prominence during his lone co…