By Christoph Steitz and Tom Sims FRANKFURT (Reuters) -Volkswagen AG, Europe’s largest carmaker, said on Friday that Russia’s invasion of Ukraine and its impact on supply chains could dent business this year, adding 2021 operating profit had doubled despite lower vehicle sales. The company also proposed to raise its annual dividend by more than half to 7.50 euros per ordinary share and 7.56 euros per preferred share, after operating profit rose to 19.3 billion euros ($21.1 billion). Carmakers are scrambling to find alternative sources of vital parts made in Ukraine from as far afield as China a…