By Hanna Rantala and Mimosa Spencer LONDON (Reuters) – French fashion label Christian Dior kicked off the holiday shopping season in London on Thursday, unveiling a Christmas spectacle at Harrods – with tennis star Emma Raducanu presiding over the event. The LVMH-owned brand outlined the London department store’s façade with lights, emblazoning the entrance with an enormous star and filling the windows with sugar sculptures and merchandise. “This is one of the biggest things we ever did together,” Pietro Beccari, Dior’s chief executive officer told Reuters, noting the brand first took over a c…