fix(3d-nds): set camera to null when switching to 2d, don't check for lags before app is booted and lower fps threshold to 30

app/components/NDS3D.vue

@@ -199,7 +199,7 @@ watch(
 
 const { onRender, onBeforeRender } = useLoop();
 
-const LAG_FPS_THRESHOLD = 40;
+const LAG_FPS_THRESHOLD = 30;
 const LAG_DURATION_SECS = 5;
 let lagSeconds = 0;
 let lagCheckDone = false;
@@ -352,7 +352,7 @@ onBeforeRender(() => {
     const delta = (now - lastFrameTime) / 1000;
     lastFrameTime = now;
 
-    if (document.hidden || delta > 0.5) {
+    if (document.hidden || delta > 0.5 || !app.booted) {
       lagSeconds = 0;
       return;
     }