fix: fix customer info listener API and add missing iOS config files

Replace non-existent Purchases.customerInfoStream with the correct
addCustomerInfoUpdateListener/removeCustomerInfoUpdateListener API.
Also add missing iOS Flutter xcconfig and AppFrameworkInfo.plist files
that are required for building.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ajpallares

e2e-tests/MaestroTestApp/ios/Flutter/AppFrameworkInfo.plist

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>CFBundleDevelopmentRegion</key>
+  <string>en</string>
+  <key>CFBundleExecutable</key>
+  <string>App</string>
+  <key>CFBundleIdentifier</key>
+  <string>io.flutter.flutter.app</string>
+  <key>CFBundleInfoDictionaryVersion</key>
+  <string>6.0</string>
+  <key>CFBundleName</key>
+  <string>App</string>
+  <key>CFBundlePackageType</key>
+  <string>FMWK</string>
+  <key>CFBundleShortVersionString</key>
+  <string>1.0</string>
+  <key>CFBundleSignature</key>
+  <string>????</string>
+  <key>CFBundleVersion</key>
+  <string>1.0</string>
+  <key>MinimumOSVersion</key>
+  <string>13.0</string>
+</dict>
+</plist>

e2e-tests/MaestroTestApp/ios/Flutter/Debug.xcconfig

@@ -0,0 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
+#include "Generated.xcconfig"

e2e-tests/MaestroTestApp/ios/Flutter/Release.xcconfig

@@ -0,0 +1,2 @@
+#include? "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
+#include "Generated.xcconfig"

e2e-tests/MaestroTestApp/lib/purchase_through_paywall_screen.dart

@@ -1,4 +1,3 @@
-import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:purchases_flutter/purchases_flutter.dart';
 import 'package:purchases_ui_flutter/purchases_ui_flutter.dart';
@@ -14,20 +13,17 @@ class PurchaseThroughPaywallScreen extends StatefulWidget {
 class _PurchaseThroughPaywallScreenState
     extends State<PurchaseThroughPaywallScreen> {
   String _entitlements = 'none';
-  StreamSubscription? _subscription;
 
   @override
   void initState() {
     super.initState();
-    _subscription = Purchases.customerInfoStream.listen((info) {
-      _updateEntitlements(info);
-    });
+    Purchases.addCustomerInfoUpdateListener(_updateEntitlements);
     Purchases.getCustomerInfo().then(_updateEntitlements);
   }
 
   @override
   void dispose() {
-    _subscription?.cancel();
+    Purchases.removeCustomerInfoUpdateListener(_updateEntitlements);
     super.dispose();
   }