fix: change initCustomerSheet return type to Future<void>

packages/stripe/lib/src/stripe.dart

@@ -679,7 +679,7 @@ class Stripe {
   }
 
   /// Initializes the customer sheet with the provided [parameters].
-  Future<CustomerSheetResult?> initCustomerSheet({
+  Future<void> initCustomerSheet({
     required CustomerSheetInitParams customerSheetInitParams,
   }) async {
     await _awaitForSettings();

packages/stripe_platform_interface/lib/src/method_channel_stripe.dart

@@ -291,18 +291,17 @@ class MethodChannelStripe extends StripePlatform {
   }
 
   @override
-  Future<CustomerSheetResult?> initCustomerSheet(
-    CustomerSheetInitParams params,
-  ) async {
+  Future<void> initCustomerSheet(CustomerSheetInitParams params) async {
     final result = await _methodChannel.invokeMethod('initCustomerSheet', {
       'params': params.toJson(),
       'customerAdapterOverrides': {},
     });
 
-    if (result is List) {
-      return null;
-    } else {
-      return _parseCustomerSheetResult(result);
+    // Check for errors only
+    // iOS returns empty array, Android returns empty map on success - both are fine
+    if (result is Map<String, dynamic> && result['error'] != null) {
+      result['runtimeType'] = 'failed';
+      throw StripeException.fromJson(result);
     }
   }
 
@@ -602,9 +601,9 @@ class MethodChannelStripe extends StripePlatform {
     }
 
     // workaround for fact that created is parsed as string from Stripe android
-    final created = result?['token']['created'];
+    final created = result['token']['created'];
     if (created != null && created is String) {
-      result?['token']['created'] = int.tryParse(created);
+      result['token']['created'] = int.tryParse(created);
     }
 
     return FinancialConnectionTokenResult.fromJson(result);

packages/stripe_platform_interface/lib/src/stripe_platform_interface.dart

@@ -75,7 +75,7 @@ abstract class StripePlatform extends PlatformInterface {
   Future<void> confirmPaymentSheetPayment();
 
   /// Configure the payment sheet using [CustomerSheetInitParams] as config.
-  Future<CustomerSheetResult?> initCustomerSheet(
+  Future<void> initCustomerSheet(
     CustomerSheetInitParams params,
   );
 

packages/stripe_web/lib/src/web_stripe.dart

@@ -58,7 +58,8 @@ class WebStripe extends StripePlatform {
 
     if (__stripe != null) {
       // Check if the new stripeAccountId or locale is different
-      if (__stripe!.stripeAccount != stripeAccountId || __stripe!.locale != locale) {
+      if (__stripe!.stripeAccount != stripeAccountId ||
+          __stripe!.locale != locale) {
         // Re-initialize with new stripeAccountId or locale
         await stripe_js.loadStripe();
         var stripeOption = stripe_js.StripeOptions();
@@ -636,7 +637,7 @@ class WebStripe extends StripePlatform {
   }
 
   @override
-  Future<CustomerSheetResult?> initCustomerSheet(
+  Future<void> initCustomerSheet(
       CustomerSheetInitParams params) {
     throw WebUnsupportedError.method('initCustomerSheet');
   }