(Refiles to remove extraneous text in the third bullet) By Harshita Mary Varghese May 1 (Reuters) - Roblox shares on Friday plunged to their lowest levels in 18 months ‌after the company cut its annual bookings forecast, raising concerns that new safety ‌measures could suppress user growth for several quarters. The videogame platform warned of "continued short-term friction" from new product changes, including ​age-based accounts, age verification and expanded content monitoring, which have restricted ...