A Chicago federal jury awarded $4.75 million Monday to three siblings who were shot several times and severely injured when a Chicago police officer fired 11 shots into the back porch of a New Year’s Eve party.Siblings Kierra, Princeton and Michael Williamson sued Chicago police officer Wilfredo Ortiz and the city in 2014, alleging he used excessive force and violated their 14th Amendment rights in the incident.The three were attending a party at their cousin’s boyfriend’s house on West 105th Street when …