Fix robot action status tracking for navigation actions

pyrobosim/pyrobosim/core/robot.py

@@ -480,7 +480,7 @@ def execute_action(self, action, blocking=False):
                     tgt_loc = action.target_location.name
 
                 self.world.gui.canvas.navigate(self, tgt_loc, action.path)
-                while self.executing_nav:
+                while blocking and self.executing_nav:
                     time.sleep(0.5)  # Delay to wait for navigation
                 success = self.last_nav_successful
             else: