Fixed ambiguity between std::byte and byte in rpcndr.h

Fixes https://github.com/libsdl-org/SDL/issues/8911

(cherry picked from commit a71f99c71f)
(cherry picked from commit 9196584773)

src/core/winrt/SDL_winrtapp_direct3d.cpp

@@ -20,12 +20,6 @@
 */
 #include "../../SDL_internal.h"
 
-/* Standard C++11 includes */
-#include <functional>
-#include <string>
-#include <sstream>
-using namespace std;
-
 /* Windows includes */
 #include "ppltasks.h"
 using namespace concurrency;

src/video/winrt/SDL_winrtvideo.cpp

@@ -29,10 +29,8 @@
  */
 
 /* Standard C++11 includes */
-#include <functional>
-#include <string>
 #include <sstream>
-using namespace std;
+#include <string>
 
 /* Windows includes */
 #include <agile.h>