Roll Dart SDK from 00784f1f22b5 to 6f8bcd5b48ab (1 revision) (flutter/engine#50074)

https://dart.googlesource.com/sdk.git/+log/00784f1f22b5..6f8bcd5b48ab

2024-01-26 dart-internal-merge@dart-ci-internal.iam.gserviceaccount.com Version 3.4.0-75.0.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,jacksongardner@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://issues.skia.org/issues/new?component=1389291&template=1850622

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

DEPS

@@ -64,7 +64,7 @@ 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': '00784f1f22b5c381cfea8d1025f711527a5b50bc',
+  'dart_revision': '6f8bcd5b48abcdd6a604d2a8a9f4362b32974404',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py