made 'name' of collection.dart nullable

lib/models/collection.dart

@@ -8,7 +8,7 @@ class Collection {
   final User? owner;
   final String encryptedKey;
   final String? keyDecryptionNonce;
-  final String name;
+  final String? name;
   final String encryptedName;
   final String nameDecryptionNonce;
   final CollectionType type;

lib/models/search/album_search_result.dart

@@ -14,7 +14,7 @@ class AlbumSearchResult extends SearchResult {
 
   @override
   String name() {
-    return collectionWithThumbnail.collection.name;
+    return collectionWithThumbnail.collection.name!;
   }
 
   @override