Heather Mack was sentenced Wednesday to 26 years in federal prison for helping to murder her mother at a Bali resort and stuff her bludgeoned body in a suitcase, sparking a sensational legal saga and led police on a trail back to suburban Chicago. Mack, 28, who pleaded guilty last year to conspiring to murder a U.S. citizen on foreign soil, has already spent nearly 10 years behind bars for the August 2014 slaying of Sheila von Wiese-Mack, including about 7 years in a prison in Indonesia. Depending on how much prior prison time Mack is given credit for, the sentence handed down by U.S. District…