By Michael Martina and David Shepardson WASHINGTON (Reuters) - Close to half of American adults support a ban on the Chinese-owned social media app TikTok, according to a new Reuters/Ipsos survey that also asked questions about national security concerns and China. TikTok, owned by Chinese tech giant ByteDance and used by tens of millions of Americans, has faced calls from U.S. lawmakers for a nationwide ban over concerns about possible Chinese government influence. Some 47% of respondents to the two-day poll, which concluded on Tuesday, said they at least somewhat supported "banning the socia...