[flutter_releases] Flutter beta 3.19.0-1.0.pre Framework Cherrypicks (#141305)

# Flutter beta 3.19.0-1.0.pre Framework

## Scheduled Cherrypicks
diff --git a/bin/internal/release-candidate-branch.version b/bin/internal/release-candidate-branch.version
new file mode 100644
index 0000000..036b1f0
--- /dev/null
+++ b/bin/internal/release-candidate-branch.version
@@ -0,0 +1 @@
+flutter-3.19-candidate.1