Remove preloading

It isn't doing anything really (when I look at results), we already have the image in memory anyway.

web/apps/cast/src/components/Slide.tsx

@@ -13,7 +13,7 @@ interface SlideViewProps {
  * Also show {@link nextURL} in an hidden image view to prepare the browser for
  * an imminent transition to it.
  */
-export const SlideView: React.FC<SlideViewProps> = ({ url, nextURL }) => {
+export const SlideView: React.FC<SlideViewProps> = ({ url }) => {
     return (
         <Container
             style={{
@@ -30,14 +30,6 @@ export const SlideView: React.FC<SlideViewProps> = ({ url, nextURL }) => {
                     backdropFilter: "blur(10px)",
                 }}
             >
-                <img
-                    src={nextURL}
-                    style={{
-                        maxWidth: "100%",
-                        maxHeight: "100%",
-                        display: "none",
-                    }}
-                />
                 <img
                     src={url}
                     decoding="sync"