By Lindsay Dunsmuir (Reuters) -Global central banks need to make clear to financial markets the probable need for interest rates to remain higher for longer in order to bring inflation sustainably back down to target and avoid a rebound in price pressures, the International Monetary Fund said on Thursday. The warning comes amid a significant easing in financial conditions since October as investors looked past the steep run up in interest rates by central banks last year designed to bring down an inflation rate that breached 6% in more than 80% of the world’s economies. Instead, as central ban…