SNEAK PREVIEW: Disney’s new streaming service, Disney+, launches next Tuesday, and tonight the company is pushing its wares by providing a sneak preview of one of its series: a weekly version, with a new cast and story, of its High School Musical franchise. It’s the least entertaining show I sampled of the new Disney+ fare, so don’t let this discourage you from considering subscribing to the new service. Presumably, the other shows will be featured in ads or excerpts