Roll Dart SDK from 9b4691f35139 to 214a7f829913 (2 revisions) (flutter#173769)

https://dart.googlesource.com/sdk.git/+log/9b4691f35139..214a7f829913

2025-08-14 [email protected]
Version 3.10.0-98.0.dev
2025-08-14 [email protected]
Version 3.10.0-97.0.dev

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/dart-sdk-flutter
Please CC [email protected],[email protected] on the revert
to ensure that a human
is aware of the problem.

To file a bug in Flutter:
https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
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Author: engine-flutter-autoroll

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': '9b4691f351395372a8964674559d0235616ca38e',
+  'dart_revision': '214a7f8299135e56d01f3fd32596636f1fb6ba94',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py