Roll Dart SDK from 5a2737b to fec6362 (2 revisions) (#35844)

Author: skia-flutter-autoroll

DEPS

@@ -36,7 +36,7 @@ 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': '5a2737b7187795a51a043f0c4cf33a465dcc48c5',
+  'dart_revision': 'fec63626f078f3b762fc667671a1e9b1a64b34bf',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py