By Johann M Cherian and Shristi Achar A (Reuters) -UK’s FTSE 100 closed higher on Monday, lifted by energy and miner stocks on steps taken by China to support its economy following a surge in COVID-19 infections in the Asian country. The export-oriented FTSE 100 climbed 0.4%, while the domestically focussed FTSE 250 gained 0.3%. Authorities in Beijing said on Friday they will focus on stabilising its $17-trillion economy in 2023 and step up policy adjustments to ensure key targets are hit. Energy and mining stocks added 2.1% and 0.5%, respectively, tracking a rise in oil and copper prices. [O/…