Fix Anycubic Chiron TFT SD menu (#21183)

Marlin/src/lcd/extui/lib/anycubic_chiron/FileNavigator.cpp

     }
     else {
       // Logical Name
-      TFTSer.print("/");
+      TFTSer.write('/');
       if (folderdepth > 0) TFTSer.print(currentfoldername);
 
       TFTSer.println(filelist.shortFilename());

Marlin/src/lcd/extui/lib/anycubic_chiron/chiron_tft.cpp

       case 15:   // A15 Resuming from outage
         if (printer_state == AC_printer_resuming_from_power_outage) {
           // Need to home here to restore the Z position
-          injectCommands(AC_cmnd_power_loss_recovery);
-          injectCommands("M1000");  // home and start recovery
+          injectCommands_P(AC_cmnd_power_loss_recovery);
+          injectCommands_P(PSTR("M1000"));  // home and start recovery
         }
         break;