Roll Dart SDK from 21574eae3a69 to 8bfec2c7ed43 (2 revisions) (#48683)

https://dart.googlesource.com/sdk.git/+log/21574eae3a69..8bfec2c7ed43

2023-12-05 [email protected] Version 3.3.0-193.0.dev
2023-12-05 [email protected] Version 3.3.0-192.0.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 [email protected],[email protected] 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://issues.skia.org/issues/new?component=1389291&template=1850622

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

Author: skia-flutter-autoroll

DEPS

@@ -59,7 +59,7 @@ 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': '21574eae3a693abda6b72933aad4bac5a2a59ca4',
+  'dart_revision': '8bfec2c7ed43bf50df1c41914666d554b4e36554',
 
   # 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: c17d2eb7a04e921c4bdced9ef3fba2fd
+Signature: 7f38d0c92f4afee2bc0fc2ad84dfeb8a
 
 ====================================================================================================
 LIBRARY: dart