By Gleb Garanich YAVORIV, Ukraine (Reuters) – Ukrainian troops in furry black-and-white winter camouflage trained on Friday firing anti-tank launchers delivered by Britain as part of Western efforts to help Ukraine defend itself from any Russian invasion. Russia has forced the West into talks on Moscow’s demands for new security guarantees in Europe by amassing more than 100,000 troops near its borders with Ukraine, a former Soviet republic that wants to join NATO. Britain said earlier this month that it would supply Ukraine with light anti-armour defensive weapon systems and personnel to prov…