fix: return null when data is still loading

src/pages/podcast.tsx

@@ -5,7 +5,7 @@ import { PodcastInfoCard } from "../components/podcast-info-card";
 export function Podcast() {
   const { podcastId } = useParams<{ podcastId: string }>();
 
-  const { data: podcast } = usePodcastQuery(podcastId);
+  const { data: podcast, isLoading } = usePodcastQuery(podcastId);
 
   if (!podcastId) {
     throw new Error(
@@ -13,6 +13,10 @@ export function Podcast() {
     );
   }
 
+  if (isLoading) {
+    return null;
+  }
+
   if (!podcast) {
     return <h1>Podcast not found</h1>;
   }