Fix some issues of printing from onboard media

[kisslorand]

Requirements

BTT or MKS TFT

Description

• when printing from (remote) onboard media and print is cancelled from a remote host (Pronterface, Octoprint, etc) the TFT will show that the print is paused, the progress stays where it was when print was cancelled, apparently the print can pe resumed ("resume" button shows up) but nothing happens (of course it doesn't since the print is already cancelled)
• a recent Marlin PR (this one) borks up the Pause/Resume procedure/logic when printing from (remote) onboard media rendering it non-functional
• when printing from (remote) onboard media the layer display type by default might want to display the layer number (if such an option was selected in the "config.ini") which is not possible since it needs the ability to parse comments from the G-code file and onboard media printing has no such capability

Benefits

This PR fixes all of the above:

• when printing from (remote) onboard media and print is cancelled from a remote host (Pronterface, Octoprint, etc) the TFT handles the cancellation as it should, as it does in all other printing situations
• the recent Marlin PR changes are adapted, more than that it is backward compatible, it handles Marlin versions with or without the mentioned PR
• when printing from (remote) onboard media the layer display type defaults to layer height display

This PR also comes with a tiny speed boost for "parseACK()" and some flash size reduction.

Related Issues

No related issues were reported, all these are my own findings.