Make kMaterialEdges const (#87329)

packages/flutter/lib/src/material/material.dart

diff --git a/packages/flutter/lib/src/material/material.dart b/packages/flutter/lib/src/material/material.dart
index c761fc5..a324199 100644
--- a/packages/flutter/lib/src/material/material.dart
+++ b/packages/flutter/lib/src/material/material.dart
@@ -54,11 +54,11 @@
 ///
 ///  * [MaterialType]
 ///  * [Material]
-final Map<MaterialType, BorderRadius?> kMaterialEdges = <MaterialType, BorderRadius?>{
+const Map<MaterialType, BorderRadius?> kMaterialEdges = <MaterialType, BorderRadius?>{
   MaterialType.canvas: null,
-  MaterialType.card: BorderRadius.circular(2.0),
+  MaterialType.card: BorderRadius.all(Radius.circular(2.0)),
   MaterialType.circle: null,
-  MaterialType.button: BorderRadius.circular(2.0),
+  MaterialType.button: BorderRadius.all(Radius.circular(2.0)),
   MaterialType.transparency: null,
 };