Car example can lose mouse up event

[willeastcott]

To reproduce:

1. Load the car example: https://playcanvas-react.vercel.app/examples/model-viewer
2. Click a couple of times in quick succession and move the mouse while you do it

Sometimes, with the mouse now up, the camera will continue to orbit the car on a mouse move. Perhaps it's related to the pointercancel event - possible because the browser thinks you're trying to drag and drop the canvas element or something.