By Shanima A (Reuters) -Britain’s largest online electricals retailer AO World on Friday issued its third profit warning in six months, sending its shares tumbling more than 19%. The company, which sells laptops, washing machines, mobile phones and printers, cited weaker consumer demand and higher costs and said that near-term revenue and profit could be hit by rising inflation, supply chain problems and belt-tightening by customers. British retailers are facing a tough backdrop as they grapple with supply chain disruption while households contend with the biggest cost-of-living squeeze since …