refactored room and file sorting to use direct comparators instead of temporary sort strings, removed obsolete 'sort' properties from API models, and improved file list sorting with case-insensitive name comparisons and null-safe date handling

lib/api/marianumcloud/talk/room/get_room_response.g.dart

@@ -60,7 +60,7 @@ GetRoomResponseObject _$GetRoomResponseObjectFromJson(
   json['status'] as String?,
   json['statusIcon'] as String?,
   json['statusMessage'] as String?,
-)..sort = json['sort'] as String?;
+);
 
 Map<String, dynamic> _$GetRoomResponseObjectToJson(
   GetRoomResponseObject instance,
@@ -97,7 +97,6 @@ Map<String, dynamic> _$GetRoomResponseObjectToJson(
   'status': instance.status,
   'statusIcon': instance.statusIcon,
   'statusMessage': instance.statusMessage,
-  'sort': instance.sort,
 };
 
 const _$GetRoomResponseObjectConversationTypeEnumMap = {