Adjust upper Dart SDK constraint (#116586)

Author: mit-mit

packages/flutter_tools/lib/src/commands/create.dart

@@ -323,8 +323,7 @@ class CreateCommand extends CreateBase {
       linux: includeLinux,
       macos: includeMacos,
       windows: includeWindows,
-      // Enable null safety everywhere.
-      dartSdkVersionBounds: "'>=$dartSdk <3.0.0'",
+      dartSdkVersionBounds: "'>=$dartSdk <4.0.0'",
       implementationTests: boolArgDeprecated('implementation-tests'),
       agpVersion: gradle.templateAndroidGradlePluginVersion,
       kotlinVersion: gradle.templateKotlinGradlePluginVersion,