A man who was body-slammed by a Chicago police officer during a 2019 arrest that was caught on video and sparked outrage pleaded guilty to spitting in the officer’s face just before the incident.Bernard Kersh, 31, pleaded guilty Thursday to a misdemeanor count of battery. In exchange for his guilty plea, Cook County prosecutors dropped aggravated battery and other charges he had faced.The judge sentenced Kersh to about a year in prison, which effectively amounted to the time he’s served, given the credit he’s earned over …