Roll Dart SDK from 49d5a2f to 01a9d4e (1 revision) (#30283)

Author: skia-flutter-autoroll

DEPS

@@ -39,7 +39,7 @@ 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': '49d5a2f58c4a9e403c6bc2b19a50a382ae422fe0',
+  'dart_revision': '01a9d4e9ede7fb3cda7327bfd07f2122027387b4',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py