[MU4] Missed case on slur-tie adjustment

[asattely]

The issue: https://user-images.githubusercontent.com/89263931/191334637-d7be94a8-1886-4186-891e-0b98dcf3264b.mp4

Notice how the slur adjusts for a tie that starts on the same note, but is not at the vertical position to be adjusted for. This has now been fixed.

[asattely]

Before we merge this one, I am going to reduce the margin for vertical collisions so we avoid stuff like this