Fix #22694: In the Staff Properties dlg box, when the instrument is changed, the list of available staff types is not updated.

(Also made more room for longer staff type names and longer list in the drop list properties)
Merge pull request #486 from mgavioli/Fix_22694_staff_type_list_on_instr_change

Fix #22694 - List of available staff type not updated on instr. change