Steam OSS' RegisterServerLink causes include of private header resulting in compile error

Steps to Reproduce

  1. In a separate module, add OnlineSubsystemSteam to PrivateDependencyModuleNames
  2. Create a new .h called FMySteamPurchasingServerLink:

`#pragma once
include “OnlinePurchaseInterfaceSteam.h”

struct FSteamPurchaseDef;

class FMySteamPurchasingServerLink
: public ISteamPurchasingServerLink
{
virtual void InitiateTransaction(const FUniqueNetId& UserId, TArray Mtxns, const FOnPurchaseCheckoutComplete& Delegate) override;
virtual void FinalizePurchase(const FUniqueNetId& UserId, const FString& ReceiptId) override;
};`1. Try and compile, resulting in the following error:

OnlinePurchaseInterfaceSteam.h(5): Error C1083 : Cannot open include file: ‘OnlineSubsystemSteamPrivate.h’: No such file or directory