A 15-year-old and a 12-year-old have been charged with making threats against Maple Shade High School in December as part of the so-called nationwide “TikTok challenge.” The 15-year-old created a TikTok account and posted videos that were “viewed and shared numerous times,” starting on Dec. 15, Maple Shade police announced Wednesday. The teen was charged with creating a false public alarm, causing/risking widespread injury or damage and cyber harassment. Police didn’t identify the teen since he or she is a juvenile. A 12-year-old was facing charges for a similar, unrelated incident, police als…