Regroup rhythms removes l.v. ties

Issue type

UX/Interaction bug (incorrect behaviour)

Description with steps to reproduce

1. Start a new score
2. Enter a note
3. Add an l.v.
4. Select the measure and run "Regroup rhythms"

Actual behaviour: The tie is removed.

Expected behaviour: The tie is not affected.

In the steps above, there isn't actually any rhythm to regroup, but the same happens in that case.

Supporting files, videos and screenshots

https://github.com/user-attachments/assets/8c973258-257b-4745-ad68-ac0334a5b421

In which versions of MuseScore Studio is this issue present?

4.5.2 – 4.6.1 nightly

Regression

I was unable to check

Operating system

macOS 12.7.6

Additional context

Possibly related to https://github.com/musescore/MuseScore/issues/26685

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

Run the listed reproduction steps in MuseScore Studio and confirm that Regroup rhythms removes the l.v. tie. Trace the implementation of the Regroup rhythms command and its handling of ties; done means the tie remains unaffected, including when there is no rhythm to regroup.