ui: fill the bg with disengaged color if not started (#35434)

fill the bg with disengaged color if not started

selfdrive/ui/onroad/augmented_road_view.py

@@ -45,7 +45,8 @@ class AugmentedRoadView(CameraView):
 
   def render(self, rect):
     # Only render when system is started to avoid invalid data access
-    if not ui_state.started:
+    if not ui_state.started or not self.frame:
+      rl.draw_rectangle_rec(rect, BORDER_COLORS[UIStatus.DISENGAGED])
       return
 
     # Update calibration before rendering