LONDON—The euro fell in thin holiday trading on Wednesday and the dollar sent the yen to a one-month low, as investors looked past surging cases of Omicron in another bout of risk appetite. Risk-sensitive currencies such as the Australian dollar were higher as stocks motored upwards but the euro bucked the trend and weakened 0.2 percent to $1.1287, while the dollar index added 0.2 percent to 96.321. With many traders having taken time off for Christmas or the end of the year, analysts said it was hard to read too much into the moves. The main driver this week was continued optimism that Omicron would not derail economic momentum. “The Omicron variant continues to rage and fails to register on this market, even as global cases topped a million for the second day running,” said Saxo Bank analysts. The dollar rose versus the safe-haven yen, gaining 0.1 percent to 114.98, …