Fix `tracks=None` bug in YOLOv8-Region-Counting module (#5977)

examples/YOLOv8-Region-Counter/yolov8_region_counter.py

@@ -120,6 +120,8 @@ def run(
 
         # Extract the results
         results = model.track(frame, persist=True)
+
+        if results[0].boxes.id is not None:
             boxes = results[0].boxes.xywh.cpu()
             track_ids = results[0].boxes.id.int().cpu().tolist()
             clss = results[0].boxes.cls.cpu().tolist()