Goldman Sachs hushed all the Facebook naysayers with a cool $450 million investment in Mark Zuckerberg’s social networking empire. Dealbook is reporting that the Wall Street giant’s investment values Facebook at $50 billion. Goldman is expected to raise as much as $1.5 billion from some of its high-net-worth investors for Facebook. According to Dealbook, Goldman has invested $450 million, and Digital Sky Technologies, a Russian investment firm that has already…