Cover art support for folder view (Subsonic servers only) (#1608)

* add coverArt support for subsonic folders

src/shared/api/subsonic/subsonic-normalize.ts

@@ -399,6 +399,8 @@ const normalizeFolder = (
             songs: results?.songs || [],
         },
         id: item.id.toString(),
+        imageId: item.coverArt?.toString() || null,
+        imageUrl: null,
         name: item.title,
         parentId: item.parent,
     };