Roll Dart SDK from fd27fda14d2b to 42976b233886 (1 revision) (flutter#31058)

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': 'fd27fda14d2b0aa0ce5b27629986e45d01fd046d',
+  'dart_revision': '42976b23388651d913bb7182f4d43ab73db4627c',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py