mus: Remove unnecessary const from property TypeConverter templates

mash/screenlock/screenlock.cc

Index: mash/screenlock/screenlock.cc
diff --git a/mash/screenlock/screenlock.cc b/mash/screenlock/screenlock.cc
index 310164d763540786f8e23ed9797e36b941cfb23f..10f32633712be199559724aef7d015427f3188f8 100644
--- a/mash/screenlock/screenlock.cc
+++ b/mash/screenlock/screenlock.cc
@@ -95,7 +95,7 @@ void Screenlock::Initialize(mojo::Connector* connector,
 
   std::map<std::string, std::vector<uint8_t>> properties;
   properties[mash::wm::mojom::kWindowContainer_Property] =
-      mojo::TypeConverter<const std::vector<uint8_t>, int32_t>::Convert(
+      mojo::ConvertTo<std::vector<uint8_t>>(
           static_cast<int32_t>(mash::wm::mojom::Container::LOGIN_WINDOWS));
   mus::Window* window =
       views::WindowManagerConnection::Get()->NewWindow(properties);