WASHINGTON — An unidentified foreign government is asking the Supreme Court to get involved in a case that may be part of special counsel Robert Mueller’s Russia investigation. The justices on Tuesday granted the government’s request to file a censored version of an appeal to the high court in which the country is fighting a grand jury subpoena and a $50,000-a-day fine for not complying with the subpoena. The appeal doesn’t identify the country, a company it controls or even the lawyers who are representing it.