Roll Dart SDK from ffbfa2000435 to 2e838b7b4503 (2 revisions) (#21039)

DEPS

@@ -34,7 +34,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': 'ffbfa200043553be1fdfaedef497e185b90a416c',
+  'dart_revision': '2e838b7b4503f055da8b90f8bc5c6c48f630812e',
 
   # 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_third_party

-Signature: d87258c3472783faf407d22721ce6725
+Signature: 1c09ff764f7d673f43411d160d4d63af
 
 UNUSED LICENSES: