By Natalia Zinets and Jonathan Landay KYIV/SLATYNE, Ukraine (Reuters) – U.S. President Joe Biden on Thursday threw his full support behind Sweden and Finland’s bids to join NATO as he and European leaders said they were confident Turkey’s surprise opposition to the Nordic states’ membership could be addressed. Meanwhile in Germany, Group of Seven financial leaders looked set to agree on Thursday and Friday on around $15 billion to help Ukraine pay its bills in coming months. Finland and Sweden say they were spurred into joining NATO by Russia’s invasion of Ukraine, reversing generations of mil…