LONDON,- Mozambican President Filipe Nyusi cannot be sued in Britain over allegations he accepted unlawful payments as part of Mozambique's litigation over the decade-long "tuna bond" scandal, London's Court of Appeal ruled on Thursday. Emirati-Lebanese shipbuilder Privinvest wanted to drag Nyusi into a $3.1-billion lawsuit brought by Mozambique, which accuses it of paying bribes to…