Position of staff text already present on staff not scaled when making staff small

I guess this case slipped through in my small staff changes.

1) new score, treble clef template
2) add staff text
3) staff properties
4) small
5) OK

Result: staff text is still the original distance from staff. Newly added texts are correct, and the existing ones fix themselves on relayout. Works for "scale" but not small. Must be connected to the call to spatiumChanged() that happens in that case, but that also leads to #287839: Changes to scale of one staff can affect elements on other staves. So the fix I think will be to do the right think on localSpatiumChanged and call that instead (for both small & scale).