Suppress deprecated iOS windows API in integration_test (flutter#173251)

Suppress the scene deprecation warning to unblock iOS 15+ deprecation
checks in the packages repo:
flutter/packages#7542

Not really part of flutter#170171, but
related problem.
Tracking issue: flutter#154365


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Author: jmagman

packages/integration_test/ios/integration_test/Sources/integration_test/IntegrationTestPlugin.m

@@ -79,7 +79,12 @@ - (void)handleMethodCall:(FlutterMethodCall *)call result:(FlutterResult)result
 
 - (UIImage *)capturePngScreenshot {
   // Get all windows in the app
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+  // TODO(jmagman) Use scenes instead of deprecated windows. See
+  // https://github.com/flutter/flutter/issues/154365
   NSArray<UIWindow *> *windows = [UIApplication sharedApplication].windows;
+#pragma clang diagnostic pop
 
   // Find the overall bounding rect for all windows
   CGRect screenBounds = [UIScreen mainScreen].bounds;