UMAR FAROOQ  A mixed martial arts specialist is challenging a Pakistani ban on TikTok, the video sharing app on which he was pinning his hopes of gaining a mass audience and helping people get fit. The Pakistan Telecommunication Authority (PTA) last week blocked access to TikTok, which is owned by China-based ByteDance, citing unspecified public complaints about "immoral and indecent content". Muhammad Ashfaq Jutt, 34, told Reuters he joined TikTok a year ago because it was becoming a popular platform and was cheaper than traditional advertising. "All kinds of people, from street sweepers to day labourers, have come to be…