Fix possible Scale Corruption in Midi Mode; disallow Lock and Group changes when scale is off

[jr0dsgarage]

Issue

When in Midi mode, if the user sets the scale to OFF after using a different scale, but then turns lock scale ON, the scale is set to a corrupted scale instead of the chromatic scale.

This leads to confusion, because none of the lights are lit up, signifying that the user should be able to play any note on the keyboard, but there are some notes that don't trigger, because the scale has become corrupted.

STR

• Set Scale to something besides OFF
• Set Scale mode to OFF
• Set Scale Lock to ON
• Try to play notes on every button

Some notes won't trigger, despite the chromatic scale being selected

This fix does two things when the Scale is set to OFF (-1)

1. When the Scale is set to OFF (aka chromatic scale), the current Lock and Group setting values are saved, and then both are set to OFF, as they are unneeded in the chromatic scale
2. When the Scale is set to anything besides OFF, the previous lock and group settings are restored!

[okyeron]

is this still an issue after Mike's 1.13.1 changes?

[Quixotic7]

That's still an issue, I'd recommend merging this.