fix for kingroon kp3s pro to avoid not start print due to shared TFT IO pins

[joseserran]

same issue as #1110 (comment)

Description

The Kingroon KP3S and other MKS ROBIN NANO based printers have been having issues with SD card prints for a couple of versions of Marlin. I have been trying different configs to see if the issue could be solved. After a lot of attempts I discovered that TFT_SHARED_IO seems to fix the issues. It would seem that the TFT and the SD card are sharing I/O. Therefore, this should be enabled in the example config.

We should also consider adding this to other examples of MKS ROBIN NANO based printers. But it should probably be on a case by case basis.

Benefits

Without this config enabled the printer would refuse to print(go back to info screen and do nothing), freeze right before printing or freeze mid print(depending on the Marlin version used)

Related Issues

[BUG] SD Card is detected but doesn't start printing or heating [BUG] On Print Start from SD Card Print Never Starts