Assertion failures and crash when adding title in any file with generated parts

[mike-spa]

Issue type

Crash or freeze

Description with steps to reproduce

1. Create file
2. Open parts
3. (From the score) Add -> Text -> Title

In debug builds this will cause an assertion failure here coming from this bit of code. The reason is that this line creates duplicate links.

By pure coincidence, those duplicates link avoid the crash reported here. Fixing the wrong code, thus avoiding the duplicate links and the assertion failures, will expose that crash.

Supporting files, videos and screenshots

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

Current master

Regression

No.

Operating system

Any

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