SendMessage throws System.NotSupportedException

<!-- Have you searched the existing issues to see if your bug is already reported? --> # Bug report ## Details ### Describe the bug SendMessage throws System.NotSupportedException ### Expected behavior SendMessage sends a direct message without an error ### Actual behavior An exception is thrown: `Unhandled exception: System.NotSupportedException: JsonTypeInfo metadata for type 'idunno.Bluesky.Chat.Model.SendMessageRequest' was not provided by TypeInfoResolver of type '[idunno.Bluesky.SourceGenerationContext, idunno.AtProto.SourceGenerationContext]'. If using source generation, ensure that all root types passed to the serializer have been annotated with 'JsonSerializableAttribute', along with any types that might be serialized polymorphically.`