SYDNEY/LONDON (Reuters) - Worker welfare is having a moment on Wall Street.The need to restart production lines and reopen offices idled by the coronavirus pandemic mean issues such as sick pay and working conditions are suddenly a top priority for the C-suite and, for some investors, a golden opportunity to apply the principles of ethical investing.Buying into companies based on environmental, social and governance (ESG) factors was growing in popularity before the virus started spreading. But..