Roll Dart SDK from 216b25f9ea6f to 7c749713c688 (1 revision) (#46284)

https://dart.googlesource.com/sdk.git/+log/216b25f9ea6f..7c749713c688

2023-09-25 dart-internal-merge@dart-ci-internal.iam.gserviceaccount.com Version 3.2.0-198.0.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-engine
Please CC dart-vm-team@google.com,jonahwilliams@google.com on the revert to ensure that a human
is aware of the problem.

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

To report a problem with the AutoRoller itself, please file a bug:
https://bugs.chromium.org/p/skia/issues/entry?template=Autoroller+Bug

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

Author: skia-flutter-autoroll

DEPS

@@ -57,7 +57,7 @@ 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': '216b25f9ea6f56a94da4a79b96016ed20c1d8dc5',
+  'dart_revision': '7c749713c688408d8fee9a58ca6c9c6fbf476f37',
 
   # 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_dart

@@ -1,4 +1,4 @@
-Signature: 8e6c2bff15fa625ee8505b718a9e9cab
+Signature: 9da25dd6e83eac28bed2aca3c9542f56
 
 ====================================================================================================
 LIBRARY: dart