How to get OTLP GRPC exporter to accept self-signed certificates?

[ejsmith]

I am sending data to an Elasticsearch APM server which support OTLP. It's using a self-signed certificate but I can not figure out how to get my app using the OTel .NET client to allow the request to work. It gets a AuthenticationException: The remote certificate is invalid because of errors in the certificate chain: PartialChain error. From what I am reading, it seems that I would need to be able to control the GrpcChannelOptions in the call to GrpcChannel.ForAddress in OtlpExporterOptionsExtensions.CreateChannel, but there does not appear to be a way to customize those options. Any ideas?