Washington CNN — Half of Americans support a US government ban on TikTok, while 22% oppose the idea and more than a quarter are unsure, according to a Pew Research Center survey released Friday. The survey results — collected in the days before and after TikTok CEO Shou Chew testified before Congress on March 23 — highlight the company’s challenges in persuading the public TikTok does not pose a national security risk. But it also underscores that significant portions of the country, 28% of Americans, remain uncertain about a ban on TikTok, suggesting they do not have firm views on…