Update Dart SDK to 1bf43bfd314768e235f6e5618842469bab6494bd

Author: christopherfujino

DEPS

@@ -56,7 +56,7 @@ 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': 'ae7ca5199a0559db0ae60533e9cedd3ce0d6ab04',
+  'dart_revision': '1bf43bfd314768e235f6e5618842469bab6494bd',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py