iOS promoted in-app purchases never fire OnPurchasePending

Steps to reproduce:

1. Create a new Unity project and install the In-App Purchasing package
2. Set up a non-consumable product in App Store Connect with promoted in-app purchases enabled
3. Implement the standard IAP v5 initialization flow (Connect, FetchProducts, FetchPurchases)
4. Register OnPurchasePending on StoreController
5. Build and run on an iOS device signed into a Sandbox account
6. Trigger a purchase intent (via itms-services URL or Xcode Transaction Manager)
7. Complete the purchase in the StoreKit payment sheet
8. See that OnPurchasePending is never called
9. Call FetchPurchases() manually
10. Observe that the purchase appears as a PendingOrder, confirming it succeeded on Apple's side but the app was never notified

Actual: No callback fires. The purchase is silently lost until the next FetchPurchases() call or app restart.
Expected: OnPurchasePending fires after the promoted purchase completes

Reproducible with: 5.2.1 (6000.0.58f2)

Reproducible on: iOS Player
Not reproducible on: No other environment tested