Locale independent totalPrice

[vlad-roid]

Summary

Fixes a major issue with Google Pay returning code 10, developer error, because totalPrice is being displayed in Eastern Arabic numerals when the locale is set to Arabic. This caused payment attempts to fail on multiple real devices.

Motivation

The Google Pay API only supports Arabic numerals 0-9, not Eastern Arabic numerals ٠-٩.

Use case:
Given my locale is set to ar_AE,
When I use Stripe's GooglePayJsonFactory.createPaymentDataRequest,
And send the JSON body to the Google Pay SDK via PaymentsClient.loadPaymentData(PaymentDataRequest.fromJson(...),
Then it should accept it without issues.
However, the Google Pay SDK call currently fails with error code 10, "developer error".

Example JSON that's sent to Google Pay currently and fails as per above:

{"apiVersion":2,"apiVersionMinor":0,"allowedPaymentMethods":[{"type":"CARD","parameters":{"allowedAuthMethods":["PAN_ONLY","CRYPTOGRAM_3DS"],"allowedCardNetworks":["AMEX","DISCOVER","MASTERCARD","VISA","JCB"]},"tokenizationSpecification":{"type":"PAYMENT_GATEWAY","parameters":{"gateway":"stripe","stripe:version":"2020-03-02","stripe:publishableKey":"..."}}}],"transactionInfo":{"currencyCode":"USD","totalPriceStatus":"FINAL","totalPrice":"٥.٠٠","checkoutOption":"COMPLETE_IMMEDIATE_PURCHASE"},"emailRequired":false,"merchantInfo":{"merchantName":"..."}}

Testing

Added test: PayWithGoogleUtilsTest.getPriceString_whenLocaleWithArabicNumerals_returnsExpectedValue

Without applying the bug fix, the test will fail as below:

value of: getPriceString(...)
expected: 1.00
but was : ١.٠٠
Expected :1.00
Actual   :١.٠٠

at com.stripe.android.PayWithGoogleUtilsTest.getPriceString_whenLocaleWithArabicNumerals_returnsExpectedValue(PayWithGoogleUtilsTest.kt:61)

[CLAassistant]

All committers have signed the CLA.

[brnunes-stripe]

Thank you for fixing!