The U.S. government has warned for years that products from China’s Huawei Technologies Co., the world’s biggest maker of telecommunications equipment, pose a national security risk for any countries that use them. As Washington has waged a global campaign to block the company from supplying state-of-the-art 5G wireless networks, Huawei and its supporters have dismissed the claims as lacking evidence. Now a Bloomberg News investigation has found a key piece of evidence underpinning the U.S. efforts — a previously unreported breach that occurred halfway around the world nearly a decade ago. In 2012, Australian intelligence officials informed their U.S. counterparts…