Refactored `ReceiptFetcher.receiptData` (#1941)
Refactored `ReceiptFetcher.receiptData` (#1941)

I'm considering adding a 4th `ReceiptRefreshPolicy` that re-fetches the
receipt N-times until it finds a transaction for a recently purchased
product ([CSDK-478]).
This will make it easier to implement.

[CSDK-478]:
https://revenuecats.atlassian.net/browse/CSDK-478?atlOrigin=eyJpIjoiNWRkNTljNzYxNjVmNDY3MDlhMDU5Y2ZhYzA5YTRkZjUiLCJwIjoiZ2l0aHViLWNvbS1KU1cifQ
RevenueCat/purchases-ios,RevenueCat/purchases-ios,RevenueCat/purchases-ios,RevenueCat/purchases-ios,RevenueCat/purchases-ios