Changed SDL_GetWindowPixelFormat() to return SDL_PixelFormat

Fixes https://github.com/libsdl-org/SDL/issues/10257
Closes https://github.com/libsdl-org/SDL/pull/10258

test/testautomation_video.c

@@ -731,7 +731,7 @@ static int video_getWindowPixelFormat(void *arg)
 {
     const char *title = "video_getWindowPixelFormat Test Window";
     SDL_Window *window;
-    Uint32 format;
+    SDL_PixelFormat format;
 
     /* Call against new test window */
     window = createVideoSuiteTestWindow(title);