By David Milliken LONDON (Reuters) -Ratings agency Standard & Poor’s cut the outlook for its AA credit rating for British sovereign debt on Friday to “negative” from “stable” as it judged Prime Minister Liz Truss’s tax cut plans would cause debt to keep rising. Finance minister Kwasi Kwarteng announced around 45 billion pounds ($50 billion) of permanent, unfunded tax cuts on Sept. 23 as well as costly temporary subsidies to household and business energy bills, sending sterling and bond markets into a tailspin. While sterling has since recovered, the Bank of England was forced to launch an emer…