Roll Dart SDK from 3a66ea7b9aaa to 1a4e3749f9a0 (1 revision) (flutter#188393)

https://dart.googlesource.com/sdk.git/+log/3a66ea7b9aaa..1a4e3749f9a0

2026-06-23 dart-internal-merge@dart-ci-internal.iam.gserviceaccount.com
Version 3.13.0-236.0.dev

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Author: engine-flutter-autoroll

DEPS

@@ -56,7 +56,7 @@ vars = {
   # updated revision list of existing dependencies. You will need to
   # gclient sync before and after update deps to ensure all deps are updated.
   # updated revision list of existing dependencies.
-  'dart_revision': '3a66ea7b9aaa7b9086d45468be6e32b1aaa2596e',
+  'dart_revision': '1a4e3749f9a06d10d078e728f16114087210def8',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py