message: Fix deli trying to nack system sent messages
diff: @@ -1235,10 +1235,16 @@ export class DeliLambda extends TypedEventEmitter<IDeliLambdaEvents> implements
  code: number,
  type: NackErrorType,
  reason: string,
  - retryAfter?: number): INackMessageOutput {
  + retryAfter?: number): INackMessageOutput | undefined {
  + const clientId = message.clientId;
  + if (!clientId) {
  + // message was sent by the system and not a client
  + // "nacking" the system is not supported
  + return undefined;
  + }
  +
  const nackMessage: INackMessage = {
  - // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
  - clientId: message.clientId!,
  + clientId,
  documentId: this.documentId,
  operation: {
  content: {
  