Examples: Improve birds compute demo. (#33016)

examples/webgpu_compute_birds.html

@@ -51,7 +51,7 @@
 			let pointer, raycaster;
 			let computeVelocity, computePosition, effectController;
 
-			const BIRDS = 16384;
+			const BIRDS = 8192;
 			const SPEED_LIMIT = 9.0;
 			const BOUNDS = 800, BOUNDS_HALF = BOUNDS / 2;