Add group prefix

lib/utils/room_name_calculator.dart

@@ -0,0 +1,16 @@
+import 'package:famedlysdk/famedlysdk.dart';
+
+class RoomNameCalculator {
+  final Room room;
+
+  const RoomNameCalculator(this.room);
+
+  String get name {
+    if (room.name.isEmpty &&
+        room.canonicalAlias.isEmpty &&
+        !room.isDirectChat) {
+      return "Group with ${room.displayname}";
+    }
+    return room.displayname;
+  }
+}