(Reuters) – The uncrewed new Boeing Starliner capsule undocked from the International Space Station on Wednesday to begin a descent back to Earth from its first journey to the outpost, nearing the end of a high-stakes test flight as NASA’s next vehicle for carrying humans to orbit. Less than a week after its launch from the Cape Canaveral U.S. Space Force Base in Florida, the CST-100 Starliner autonomously separated from the space station at 2:36 p.m. EDT (1836 GMT) to embark on a five-hour-plus return flight. The undocking occurred as the two vehicles were orbiting 257 miles over Singapore, c…