Fix error when trying to create payment in languages which use , instead of .

core-util/src/main/java/org/signal/core/util/money/FiatMoney.java

@@ -5,6 +5,7 @@ import androidx.annotation.NonNull;
 import java.math.BigDecimal;
 import java.text.NumberFormat;
 import java.util.Currency;
+import java.util.Locale;
 
 public class FiatMoney {
   private final BigDecimal amount;
@@ -37,7 +38,14 @@ public class FiatMoney {
    * @return amount, rounded to the default fractional amount.
    */
   public @NonNull String getDefaultPrecisionString() {
-    NumberFormat formatter = NumberFormat.getInstance();
+    return getDefaultPrecisionString(Locale.getDefault());
+  }
+
+  /**
+   * @return amount, rounded to the default fractional amount.
+   */
+  public @NonNull String getDefaultPrecisionString(@NonNull Locale locale) {
+    NumberFormat formatter = NumberFormat.getInstance(locale);
     formatter.setMinimumFractionDigits(currency.getDefaultFractionDigits());
     formatter.setGroupingUsed(false);
 

donations/lib/src/main/java/org/signal/donations/GooglePayApi.kt

@@ -17,6 +17,7 @@ import org.json.JSONException
 import org.json.JSONObject
 import org.signal.core.util.logging.Log
 import org.signal.core.util.money.FiatMoney
+import java.util.Locale
 
 /**
  * Entrypoint for Google Pay APIs
@@ -124,7 +125,7 @@ class GooglePayApi(
       put("currencyCode", price.currency.currencyCode)
       put("countryCode", "US")
       put("totalPriceStatus", "FINAL")
-      put("totalPrice", price.defaultPrecisionString)
+      put("totalPrice", price.getDefaultPrecisionString(Locale.US))
       put("totalPriceLabel", label)
       put("checkoutOption", "COMPLETE_IMMEDIATE_PURCHASE")
     }