By Jason Lange WASHINGTON (Reuters) – One of the biggest Democratic Party fundraising groups on Monday said it filed a complaint with the Federal Election Commission accusing Donald Trump of breaking campaign finance law by spending political donations on a 2024 U.S. presidential bid he has yet to formally launch. The complaint by the American Bridge group says Trump’s Save America fund is promoting him as if he were a candidate. As a leadership committee, the Save America fund can pay for such political activities as Trump’s travel, hotel stays and contributions to political allies. But by la…