Enlarge this image In a newly public letter, TikTok's top executive, Shou Zi Chew, tried to allay the concerns of several U.S. senators about the Chinese-owned company's data security practices. Kiichiro Sato/AP hide caption toggle caption Kiichiro Sato/AP In a newly public letter, TikTok's top executive, Shou Zi Chew, tried to allay the concerns of several U.S. senators about the Chinese-owned company's data security practices. Kiichiro Sato/AP TikTok is working on a deal with the Biden administration that would "fully safeguard" the app in the U.S. and quell fears about the Chinese government's accessing Americans' data, according to a letter…