awaitStorefrontCountryCode
This method will try to obtain the Store (Google/Amazon) country code in ISO-3166-1 alpha2. If there is any error, it will return null and log said error. Coroutine friendly version of Purchases.getStorefrontCountryCode.
Return
The Store country code in ISO-3166-1 alpha2.
Throws
with a PurchasesError if there's an error retrieving the country code.