Allow browser context menu for images in reader (#524)

The changes of dabe88385d removed the ability to copy/open images in a new tab due to enabling scrolling via left mouse click and dragging the mouse.

src/components/util/SpinnerImage.tsx

@@ -59,7 +59,7 @@ export function SpinnerImage(props: IProps) {
         return <Box sx={spinnerStyle} />;
     }
 
-    return <img style={imgStyle} ref={imgRef} src={imageSrc} alt={alt} />;
+    return <img style={imgStyle} ref={imgRef} src={imageSrc} alt={alt} draggable={false} />;
 }
 
 SpinnerImage.defaultProps = {