A young child who died in the southwest suburbs Sunday night has prompted a homicide investigation, with the Will County sheriff’s office and the Department of Family and Child Services all involved as detectives work to learn more. The incident unfolded about 5:53 p.m. in Plainfield, a release from the Will County sheriff’s office said, with sheriff’s deputies called to a home in the 14100 block of Lehigh Drive. According to authorities, the de…