BERLIN (Reuters) – Britain’s defence intelligence service believes that Russia’s momentum in the war in Ukraine will slow in the next few months as its army exhausts its resources, British Prime Minister Boris Johnson told a group of European newspapers. In comments released on Wednesday by Germany’s Sueddeutsche Zeitung, Johnson said President Vladimir Putin’s forces were pushing forward in the eastern Donbas region, wreaking destruction but at a heavy cost in soldiers and weapons. “Our defence intelligence service believes, however, that in the next few months, Russia could come to a point a…