[flutter_releases] Flutter stable 3.19.4 Engine Cherrypicks (#51532)

# Flutter stable 3.19.4 Engine

## Scheduled Cherrypicks

- Roll dart revision: dart-lang/sdk@bc4150a9a
diff --git a/DEPS b/DEPS
index 8da5bab..98900f9 100644
--- a/DEPS
+++ b/DEPS
@@ -66,7 +66,7 @@
   # 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': 'd62c54ebed698399afc8c28efc8cdaacbc056327',
+  'dart_revision': 'bc4150a9a23da4b3497c1d76b196e97a3e10b6cc',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py
diff --git a/ci/licenses_golden/licenses_dart b/ci/licenses_golden/licenses_dart
index 3c6abdf..aeb20a1 100644
--- a/ci/licenses_golden/licenses_dart
+++ b/ci/licenses_golden/licenses_dart
@@ -1,4 +1,4 @@
-Signature: 64351e15db1179a4fa69a24bc1a43c42
+Signature: 7885e42ed0f5466417fae174c1ce5fac
 
 ====================================================================================================
 LIBRARY: dart