[fuchsia_scenic_flutter] update dependencies

Adds the "//sdk/fidl/fuchsia.ui.gfx" dependency
as an explicit dependency.

Change-Id: I62d59d0eda22db56d52643c05b8179e51a970234
diff --git a/public/dart/fuchsia_scenic_flutter/BUILD.gn b/public/dart/fuchsia_scenic_flutter/BUILD.gn
index 5c5838b..9dee110 100644
--- a/public/dart/fuchsia_scenic_flutter/BUILD.gn
+++ b/public/dart/fuchsia_scenic_flutter/BUILD.gn
@@ -28,6 +28,7 @@
   deps = [
     "//sdk/fidl/fuchsia.math",
     "//sdk/fidl/fuchsia.sys",
+    "//sdk/fidl/fuchsia.ui.gfx",
     "//sdk/fidl/fuchsia.ui.viewsv1",
     "//sdk/fidl/fuchsia.ui.viewsv1token",
     "//third_party/dart-pkg/git/flutter/packages/flutter",