By Noor Zainab Hussain, Jonathan Saul and Carolyn Cohn LONDON (Reuters) – The commercial arm of French insurer AXA is reducing cover offered to aviation companies as it seeks to protect the multibillion-euro business after heavy Ukraine-related losses, two underwriting and broking sources told Reuters. One of the top 10 players in global aviation insurance, AXA XL is pulling back from underwriting risk on so-called war cover, the sources said, reducing options for airline operators or lessors seeking protection against loss or damage arising from war. The retreat by a major player such as AXA …