React-native-iap: Implement canMakePayments for iOS

[vshab]

Hello.

According to Apple guidline https://developer.apple.com/library/content/documentation/NetworkingInternet/Conceptual/StoreKitGuide/Chapters/ShowUI.html

Display a store only if the user can make payments. To determine whether the user can make payments, call the canMakePayments class method of the SKPaymentQueue class. If the user can’t make payments (for example, because of parental restrictions), either display UI indicating that that the store isn’t available or omit the store portion of your UI entirely.

It would be really nice to have canMakePayments(https://developer.apple.com/documentation/storekit/skpaymentqueue/1506139-canmakepayments?language=objc) exposed to JS.

Thanks.

[JJMoon]

OK. We will implement the function soon.

[hyochan]

@vshab This is released in [email protected]. Sorry for late update. JJMoon hasn't been working on this one! Please reopen when there is an issue. This will be called in prepare method in our module.