Move to Flutter 3.47, use the improvements that come with this (#64)

Reviewed-on: #64

lib/models/requests/join_room.dart

@@ -1,14 +1,16 @@
 import "package:fast_immutable_collections/fast_immutable_collections.dart";
 import "package:freezed_annotation/freezed_annotation.dart";
+
 part "join_room.freezed.dart";
 part "join_room.g.dart";
 
-@freezed
-abstract class JoinRoomRequest with _$JoinRoomRequest {
-  const factory JoinRoomRequest({
-    required String roomIdOrAlias,
-    @Default(IList.empty()) IList<String> via,
-  }) = _JoinRoomRequest;
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const JoinRoomRequest({
+  required final String roomIdOrAlias,
+  final IList<String> via = const IList.empty(),
+}) with _$JoinRoomRequest {
+  Map<String, Object?> toJson() => _$JoinRoomRequestToJson(this);
 
   factory JoinRoomRequest.fromJson(Map<String, Object?> json) =>
       _$JoinRoomRequestFromJson(json);