Roll Dart SDK from 0c121a6431cc to a2ea759c16cc (1 revision) (#45384)

https://dart.googlesource.com/sdk.git/+log/0c121a6431cc..a2ea759c16cc

2023-09-01 dart-internal-merge@dart-ci-internal.iam.gserviceaccount.com Version 3.2.0-129.0.dev

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter-engine
Please CC aaclarke@google.com,dart-vm-team@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Flutter Engine: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

DEPS

@@ -57,7 +57,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/main/DEPS
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': '0c121a6431cc6de5732f5638caf887df3280d148',
+  'dart_revision': 'a2ea759c16cc465f26ff632cc50a441ae84d9862',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py

ci/licenses_golden/licenses_dart

@@ -1,4 +1,4 @@
-Signature: bb2b58652a7f461a1d4d8cc430776313
+Signature: fc486989d2c0bac703b4bca873650391
 
 ====================================================================================================
 LIBRARY: dart