Use GetTempPathW() instead of GetTempPath2W()

GetTempPath2() is only available on Windows 11 and Windows 10 systems with full updates. We want to be compatible back to earlier versions of Windows and the only difference between the two calls is the behavior for processes running as SYSTEM, which we don't expect for SDL applications using notifications.

src/notification/windows/SDL_windowsnotification.c

@@ -372,12 +372,12 @@ static WCHAR *SaveToastImage(SDL_Surface *icon)
             KillTimer(NULL, cleanup_timer_id);
         }
 
-        path_len = GetTempPath2W(0, NULL);
+        path_len = GetTempPathW(0, NULL);
         if (!path_len) {
             return NULL;
         }
         temp_path = SDL_realloc(temp_path, (path_len + 1) * sizeof(WCHAR));
-        path_len = GetTempPath2W((DWORD)path_len + 1, temp_path);
+        path_len = GetTempPathW((DWORD)path_len + 1, temp_path);
         if (!path_len) {
             SDL_free(temp_path);
             return NULL;