iOS: Support older SDKs

modules/juce_product_unlocking/native/juce_ios_InAppPurchases.cpp

@@ -109,7 +109,7 @@ struct InAppPurchases::Pimpl   : public SKDelegateAndPaymentObserver
         String getContentVersion() const override  { return nsStringToJuce (download.contentVersion); }
 
       #if JUCE_IOS
-        int64 getContentLength()   const override  { return download.expectedContentLength; }
+        int64 getContentLength()   const override  { return download.contentLength; }
         Status getStatus()         const override  { return SKDownloadStateToDownloadStatus (download.downloadState); }
       #else
         int64 getContentLength()   const override  { return download.expectedContentLength; }