Revert Dart SDK to 3245b92a5930 (#49727)

A recent Dart SDK roll included a regression affecting runs of "flutter analyze" on individual files

(see https://dart.googlesource.com/sdk/+/89bd370e95c0695250a4f0111be3134b9936eadd)

Author: jason-simmons

DEPS

@@ -65,7 +65,7 @@ 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': '6f5bd26b293dde135305e5df72430644b61e3452',
+  'dart_revision': '3245b92a593090a7463abaf22c810a8080ec1ffa',
 
   # 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: 6569168d9974bb85cb3ed3a2a2e41857
+Signature: 708b5d2466539fe817747cc627e7ac58
 
 ====================================================================================================
 LIBRARY: dart
@@ -4707,7 +4707,7 @@ Exhibit B - "Incompatible With Secondary Licenses" Notice
   This Source Code Form is "Incompatible With Secondary Licenses", as
   defined by the Mozilla Public License, v. 2.0.
 
-You may obtain a copy of this library's Source Code Form from: https://dart.googlesource.com/sdk/+/6f5bd26b293dde135305e5df72430644b61e3452
+You may obtain a copy of this library's Source Code Form from: https://dart.googlesource.com/sdk/+/3245b92a593090a7463abaf22c810a8080ec1ffa
 /third_party/fallback_root_certificates/
 
 ====================================================================================================

sky/packages/sky_engine/LICENSE

@@ -31204,7 +31204,7 @@ Exhibit B - "Incompatible With Secondary Licenses" Notice
   This Source Code Form is "Incompatible With Secondary Licenses", as
   defined by the Mozilla Public License, v. 2.0.
 
-You may obtain a copy of this library's Source Code Form from: https://dart.googlesource.com/sdk/+/6f5bd26b293dde135305e5df72430644b61e3452
+You may obtain a copy of this library's Source Code Form from: https://dart.googlesource.com/sdk/+/3245b92a593090a7463abaf22c810a8080ec1ffa
 /third_party/fallback_root_certificates/
 
 --------------------------------------------------------------------------------