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

Reviewed-on: #64

lib/models/configs/members_by_status.dart

@@ -1,14 +1,16 @@
 import "package:freezed_annotation/freezed_annotation.dart";
 import "package:nexus/models/membership_status.dart";
+
 part "members_by_status.freezed.dart";
 part "members_by_status.g.dart";
 
-@freezed
-abstract class MembersByStatusConfig with _$MembersByStatusConfig {
-  const factory MembersByStatusConfig({
-    required String roomId,
-    required MembershipStatus status,
-  }) = _MembersByStatusConfig;
+@Freezed(toJson: false, fromJson: false)
+@JsonSerializable()
+class const MembersByStatusConfig({
+  required final String roomId,
+  required final MembershipStatus status,
+}) with _$MembersByStatusConfig {
+  Map<String, Object?> toJson() => _$MembersByStatusConfigToJson(this);
 
   factory MembersByStatusConfig.fromJson(Map<String, Object?> json) =>
       _$MembersByStatusConfigFromJson(json);