Changing barline type in part affects only that staff in score

Here's something I missed in my recent changes to barlines:

1) open or create a score for multiple instruments with parts
2) view a non-empty part (or an empty one, but disable mmrests)
3) change a regular barline to double
4) view score

Result: the change is properly linked, but it doesn't apply to other staves in the score. Works as expected if you change the barline in the score.

To be honest, while I was working barlines recently, I was aware of this but thought of it as potentially desirable behavior. But I suspect it isn't most of the time, and it's not how 2.3.2 worked.

Easy enough to fix in uncoChangeBarlineType(), instead of looping through the staves of the current score, we should loop through the staves of the master score.