Update FakePedestrianDetector2D to generate more dynamic pedestrian

Author: Shiyang-Zhao

GEMstack/onboard/perception/pedestrian_detection.py

@@ -144,4 +144,4 @@ def update(self, vehicle: VehicleState) -> Dict[str, AgentState]:
                 res[agent_id] = box_to_fake_agent((x_new, y_new, 0, 0))
 
         print(f"Currently tracking {len(self.pedestrians)} pedestrians")
-        return res
+        return res