MANUAL STEPPER SYNC and FORCE_MOVE behavior issue in latest

This commit does not touch the motion subsystem, so I suspect it has been broken later.
It would be helpful if you could identify where it has been broken: Klipper Versioning, Downgrading, and Bisecting

It is sort of a “cut”/knife move for MMU?

I’m personally a little surprised that FORCE_MOVE plays well with other motions in the system.
So, I’m not sure it was intended to work, or that there was a change that explicitly removed this functionality.

(Btw, I suspect it could be emulated with an extra axis: G-Codes - Klipper documentation)

Thanks.