FILE – The icon for the video-sharing TikTok app is seen on a smartphone, on Feb. 28, 2023. FILE – The icon for the video-sharing TikTok app is seen on a smartphone, on Feb. 28, 2023. FILE – The icon for the video-sharing TikTok app is seen on a smartphone, on Feb. 28, 2023. FILE – The icon for the video-sharing TikTok app is seen on a smartphone, on Feb. 28, 2023. The investigation found that the sign-up process for teen users resulted in settings that made their accounts public by default. LONDON — European regulators slapped TikTok with a…