Fixes crash

Author: velopert

src/containers/post/HorizontalAd.tsx

@@ -22,7 +22,8 @@ function HorizontalAd({}: Props) {
         threshold: 0,
       },
     );
-    observer.observe(ref.current!);
+    if (!ref.current) return;
+    observer.observe(ref.current);
     return () => {
       observer.disconnect();
     };