By Sabine Siebold and Sarah Marsh MUENSTER, Germany (Reuters) -Group of Seven foreign ministers gathered on Thursday to weigh how to support Ukraine through the winter in the face of Russian attacks on its power grid as well as deal with China’s growing assertiveness and Iran’s crackdown on protests. The two-day meeting in Germany comes amid concerns over the consistency of Western support for Ukraine against Russia’s invasion, amid leadership changes across Europe and a possible U.S. Republican victory in next week’s midterm elections. The top diplomats of the G7 rich democracies will join se…