fix #41721: bad layout of melisma lines in parts

There are two fixes that seem to work equaly well in my brief testing.  Either don't clone lyric lines at all when creating parts (they are re-generated on layout), or be sure to re-parent the copied lines to the new lyric.  I implemented the latter but then ifdef'ed out the whole copy, meaning I'm really doing the former.  I realize the implementation of melisma lines may be changing soon anyhow, but even so, seems this code could be useful to reference.  Also, even though I don't know of any visible bugs with hyphen layout, they presumably have the same underlying issue (wrong parent), which this PR fixes as well.