Ties on cross-staff grace notes do not move with notes
As see in cross-staff ties.mscz in measure 2.
When you tie a grace note to a main note and move both using cross staff notation, the tie is displayed on the wrong staff. It's actually in the position it needs to be if it were on the other staff.
Workaround is to disable auto placement and use the Y offset to move the slur. This isn't bad for my example of 1 but quite tedious when there are a dozen (over a few measures) and you're also moving accidentals in the destination staff so they don't obscure the grace notes. I made this major due to the complexity of the workaround.
Relates to #285233: [EPIC] Cross-staff notation issues