fix: resolve type error from useRef return

See for where the solution came from DefinitelyTyped/DefinitelyTyped#35572 (comment)

src/components/NewsCarousel/NewsCarousel.tsx

@@ -20,7 +20,7 @@ const CustomEllipse = ({ onClick }: any) => {
 }
 
 const NewsCarousel = ({ articles }: { articles: ArticleListItemRecord[] }) => {
-  const sliderRef = useRef<Slider>()
+  const sliderRef = useRef<Slider>(null)
 
   const settings = {
     dots: true,