fix(llc): make message.i18n readonly

Signed-off-by: xsahil03x <[email protected]>

packages/stream_chat/lib/src/core/models/message.dart

@@ -217,7 +217,7 @@ class Message extends Equatable {
   bool get isEphemeral => type == 'ephemeral';
 
   /// A Map of translations.
-  @JsonKey(includeIfNull: false)
+  @JsonKey(includeIfNull: false, toJson: Serializer.readOnly)
   final Map<String, String>? i18n;
 
   /// Known top level fields.

packages/stream_chat/lib/src/core/models/message.g.dart

@@ -108,6 +108,6 @@ Map<String, dynamic> _$MessageToJson(Message instance) {
   val['pin_expires'] = instance.pinExpires?.toIso8601String();
   val['pinned_by'] = readonly(instance.pinnedBy);
   val['extra_data'] = instance.extraData;
-  writeNotNull('i18n', instance.i18n);
+  writeNotNull('i18n', readonly(instance.i18n));
   return val;
 }