[cupertino/dialog.dart] CupertinoPopupSurface: remove bounded parameter from ImageFilterConfig.blur (#182195)

Removed 'bounded: true' from ImageFilterConfig.blur until
https://github.com/flutter/flutter/issues/182066 is resolved. This
should unblock https://github.com/flutter/flutter/pull/182036.

See comment:
https://github.com/flutter/flutter/issues/182066#issuecomment-3881321273

@dkwingsmt 

Before:
<img width="600" alt="Before"
src="https://github.com/user-attachments/assets/29573ca2-eef7-4443-947c-58a7d30d060d"
/>

After:
<img width="600" alt="After"
src="https://github.com/user-attachments/assets/abae388a-ff40-494e-8137-13083e05ea81"
/>

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packages/flutter/lib/src/cupertino/dialog.dart

diff --git a/packages/flutter/lib/src/cupertino/dialog.dart b/packages/flutter/lib/src/cupertino/dialog.dart
index f2f6db5..1f0335b 100644
--- a/packages/flutter/lib/src/cupertino/dialog.dart
+++ b/packages/flutter/lib/src/cupertino/dialog.dart
@@ -679,6 +679,8 @@
   /// Defaults to true.
   static bool debugIsVibrancePainted = true;
 
+  // TODO(davidhicks980): Set `bounded` to true on ImageFilterConfig.blur after
+  // https://github.com/flutter/flutter/issues/182066 is resolved.
   ImageFilterConfig? _buildFilter(Brightness? brightness) {
     var isVibrancePainted = true;
     assert(() {
@@ -689,7 +691,7 @@
       if (blurSigma == 0) {
         return null;
       }
-      return ImageFilterConfig.blur(sigmaX: blurSigma, sigmaY: blurSigma, bounded: true);
+      return ImageFilterConfig.blur(sigmaX: blurSigma, sigmaY: blurSigma);
     }
 
     final colorFilter = ImageFilterConfig(switch (brightness) {
@@ -703,7 +705,7 @@
 
     return ImageFilterConfig.compose(
       inner: colorFilter,
-      outer: ImageFilterConfig.blur(sigmaX: blurSigma, sigmaY: blurSigma, bounded: true),
+      outer: ImageFilterConfig.blur(sigmaX: blurSigma, sigmaY: blurSigma),
     );
   }
 

packages/flutter/test/cupertino/popup_surface_test.dart

diff --git a/packages/flutter/test/cupertino/popup_surface_test.dart b/packages/flutter/test/cupertino/popup_surface_test.dart
index 4f87312..d31514b 100644
--- a/packages/flutter/test/cupertino/popup_surface_test.dart
+++ b/packages/flutter/test/cupertino/popup_surface_test.dart
@@ -9,6 +9,7 @@
 
 import 'package:flutter/cupertino.dart';
 import 'package:flutter/foundation.dart';
+import 'package:flutter/rendering.dart';
 import 'package:flutter_test/flutter_test.dart';
 
 class _FilterTest extends StatelessWidget {
@@ -338,4 +339,27 @@
       matchesGoldenFile('cupertinoPopupSurface.composition.png'),
     );
   });
+
+  // Regression test for https://github.com/flutter/flutter/issues/182066.
+  testWidgets('CupertinoPopupSurface uses unbounded blur', (WidgetTester tester) async {
+    void expectContainsUnboundedBlur() {
+      var foundBlur = false;
+      for (final Layer layer in tester.layers) {
+        if (layer is BackdropFilterLayer) {
+          if (layer.toString().contains('blur')) {
+            expect(layer.toString(), isNot(contains('bounds: ')));
+            foundBlur = true;
+          }
+        }
+      }
+      expect(foundBlur, isTrue);
+    }
+
+    await tester.pumpWidget(
+      const CupertinoApp(
+        home: Center(child: CupertinoPopupSurface(child: Text('X'))),
+      ),
+    );
+    expectContainsUnboundedBlur();
+  });
 }