[Accessibility] Fix heading level gaps (#39149)

app/javascript/mastodon/components/status.jsx

@@ -556,7 +556,7 @@ class Status extends ImmutablePureComponent {
       ).find((item) => compareUrls(item.get('url'), cardUrl));
   
       if (taggedCollection) {
-        media = <CollectionPreviewCard collection={taggedCollection.toJS()} />;
+        media = <CollectionPreviewCard collection={taggedCollection.toJS()} headingLevel='h2' />;
       } else {
         media = (
           <Card
@@ -570,7 +570,7 @@ class Status extends ImmutablePureComponent {
       const firstLinkedCollection = status.get('tagged_collections').first();
       if (firstLinkedCollection) {
         media = (
-          <CollectionPreviewCard collection={firstLinkedCollection.toJS()} />
+          <CollectionPreviewCard collection={firstLinkedCollection.toJS()} headingLevel='h2' />
         );
       }
     }