By Sarah Mills and Will Russell WINDSOR, England (Reuters) – After the shame of Prince Andrew’s U.S. sex abuse lawsuit and Prince Charles embroilment in a cash for honours scandal, Queen Elizabeth catching COVID-19 has rounded off a week of terrible news for the British royals. Buckingham Palace said on Sunday the monarch, who turns 96 in two months, was suffering mild symptoms after testing positive for the virus. But growing health fears and scandals involving the family are threatening to overshadow national celebrations to mark her 70th anniversary on the throne. “I suspect this is not a w…