message: unregister server_disconnect from the correct object
diff: @@ -460,7 +460,7 @@ export class OdspDocumentDeltaConnection extends DocumentDeltaConnection {
  };
  }
  - this.socketReference!.once("server_disconnect", this.serverDisconnectHandler);
  + this.socketReference!.on("server_disconnect", this.serverDisconnectHandler);
  this.socket.on("get_ops_response", (result: IGetOpsResponse) => {
  const messages = result.messages;
  @@ -585,9 +585,9 @@ export class OdspDocumentDeltaConnection extends DocumentDeltaConnection {
  protected disconnect(socketProtocolError: boolean, reason: IAnyDriverError) {
  const socket = this.socketReference;
  assert(socket !== undefined, 0x0a2 /* "reentrancy not supported!" */);
  - this.socketReference = undefined;
  - this.socket.off("server_disconnect", this.serverDisconnectHandler);
  + this.socketReference?.off("server_disconnect", this.serverDisconnectHandler);
  + this.socketReference = undefined;
  if (!socketProtocolError && this.hasDetails) {
  // tell the server we are disconnecting this client from the document
  