Repeat measure number positioned correctly on all staves

[miiizen]

Resolves: #18961

Adjusts repeat measure number to clear whichever's highest - the top staff line, repeat symbol or, in the case of a 1 line stave, the barline

• I signed the CLA
• The title of the PR describes the problem it addresses
• Each commit's message describes its purpose and effects, and references the issue it resolves
• If changes are extensive, there is a sequence of easily reviewable commits
• The code in the PR follows the coding rules
• There are no unnecessary changes
• The code compiles and runs on my machine, preferably after each commit individually
• I created a unit test or vtest to verify the changes I made (if applicable)