Add latest path reset

pyrobosim/pyrobosim/navigation/a_star.py

@@ -133,6 +133,7 @@ def neighbors(self, cell):
 
     def reset(self):
         """Resets the occupancy grid."""
+        self.latest_path = Path()
         self.grid = OccupancyGrid.from_world(
             self.world,
             resolution=self.grid_resolution,