Former US president and current White House hopeful Donald Trump has joined TikTok, posting his first video on the wildly popular social media app he once tried to ban while in office. Reaching out to younger voters as he seeks reelection in November, Trump posted a 13-second clip Saturday night that shows him in his usual blue suit and red tie attending an Ultimate Fighting Championship bout in Newark, New Jersey. In the video, which features raucous music, Trump is introduced by UFC CEO Dana White and leans into the camera saying, “It’s my honor.” Trump greets people at the UFC arena and con…