Fix Anycubic I3 Mega (S) original screen % display (#19210)

Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp

 #include "../../../../inc/MarlinConfig.h"
 #include "../../ui_api.h"
 #include "../../../../MarlinCore.h" // for quickstop_stepper and disable_steppers
+#include "../../../../module/motion.h"	// for A20 read printing speed feedrate_percentage
 
 // command sending macro's with debugging capability
 #define SEND_PGM(x)                                 send_P(PSTR(x))
     uint16_t selectedNumber = 0;
     SelectedDirectory[0] = 0;
     SelectedFile[0] = 0;
+    ExtUI::FileList currentFileList;                                 
 
     SENDLINE_PGM("FN "); // Filelist start
 
 
       if (SpecialMenu)
         RenderSpecialMenu(selectedNumber);
-      else
+      else if (selectedNumber <= currentFileList.count())
         RenderCurrentFolder(selectedNumber);
     }
     SENDLINE_PGM("END"); // Filelist stop
             break;
 
           case 20: { // A20 read printing speed
-            int16_t feedrate_percentage = 100;
 
             if (CodeSeen('S'))
               feedrate_percentage = constrain(CodeValue(), 40, 999);