Fix #23538: update accidentals when tie is deleted

[heuchi]

UPDATED: This is to fix #23538 (formerly #12116):

Added call to updateAccidentals() in Chord::remove(Element_) and Note::remove(Element_) to make sure, notes which are no longer tied back get needed accidentals. This was the described issue #23538.

Let RemoveElement::undo() reset the tieBack property of the tie's endNote when restoring a removed tie, to avoid crashes.

Added a call to updateAccidentals() for the end measure of a tie being removed in RemoveElement::redo():
Example: Key signature of F major, a B nat is tied to the next measure which contains a second B nat.
This second B nat needs an accidental because the tied note doesn't have one. If the tie is removed, the first note gets a natural and now the second one does no longer need one. Therefore we need to check the measure of the last note of the tie.