Make Soloist Button Does Nothing

[Fourniture]

Issue type

Engraving bug (incorrect score rendering)

Description with steps to reproduce

1. Create a score with multiple instruments, say a vocal score with sopranos and a soprano soloist.
2. Select one of the sopranos and click "make soloist"
3. Create score and see that the Sopranos are listed as Sopranos 1 and 2, with a bracket joining them; both of which are incorrect for a soloist setup.

Supporting files, videos and screenshots

"Make Soloist" selected:

Result:

Expected Result:

In which versions of MuseScore Studio is this issue present?

OS: Windows 11 Version 24H2 or later, Arch.: x86_64, MuseScore Studio version (64-bit): 4.6.4-253351238, revision: github-musescore-musescore-8af129b

Regression

I was unable to check

Operating system

Windows 11

Additional context

No response

Checklist

• This report follows the guidelines for reporting bugs and issues
• I have verified that this issue has not been logged before, by searching the issue tracker for similar issues
• I have attached all requested files and information to this report
• I have attempted to identify the root problem as concisely as possible, and have used minimal reproducible examples where possible