Section break is unlinked with parts and may cause score corruption

[mercuree]

Issue type

File corruption

Description with steps to reproduce

1. Create score with one or more staves
2. Open parts
3. Add section break
4. Save/close/reopen
5. a) Removed section break in full score remains in parts
   b) changing rest in a measure with section break will make score corrupted

Supporting files, videos and screenshots

section_break_corruption1.mp4

section_break_corruption2.mp4

What is the latest version of MuseScore Studio where this issue is present?

MuseScore Studio version (64-bit): 4.5.0-242730311, revision: github-musescore-musescore-5fd9c73

Regression

I was unable to check

Operating system

windows 10

Additional context

I could reproduce in MS 4.0.2, 4.3.2, 4.4.2, 4.5.0 nightly
This issue is based on report from musescore.org, although I was unable to reproduce the original problem with extra measures.

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