Roll Dart SDK from 7cbd8dc183c0 to 31310f2db06b (1 revision) (#35610)

DEPS

diff --git a/DEPS b/DEPS
index 08cd7b1..6157c2c 100644
--- a/DEPS
+++ b/DEPS
@@ -36,7 +36,7 @@
   # 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': '7cbd8dc183c04b61127eff684e5e4dfea2456623',
+  'dart_revision': '31310f2db06bff139d9efc69dbdc7c1e82345faf',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py