Crash when parts contain desynced elements

[mercuree]

Issue type

Crash or freeze

Bug description

Musescore crashes when user tries to change visibility for other instruments in parts. It happens if part for some unknown reason contains "desynced element" - some element in parts, which does not contain <linked/> tag inside (when moving it does not become orange).
Initially it was reported here, but I couldn't reproduce it from scratch.
The author wrote:

I had done a bit of copy/pasting: opened a midi file in Musescore 3, edited and saved as a Musescore file, opened in Musescore 4, and pasted it in my score.

This is a rare case, low priority is absolutely fine for it.

Steps to reproduce

1. Open score Experiments from the N-Space 2 - Jan Update.mscz.zip (remove zip extension after download)
2. Open Guitar part.
3. Go to Instruments palette and make Tenor Saxophone instrument visible
4. Crash

Screenshots/Screen recordings

Crash:

crash_with_desynced_element.mp4

No crash if removing bad element

no_crash_if_removing_desynced_element.mp4

MuseScore Version

OS: Windows 10 Version 2009 or later, Arch.: x86_64, MuseScore version (64-bit): 4.3.0-240260304, revision: github-musescore-musescore-75a9232

Also Musescore 4.2.0 and 4.2.1

Regression

I don't know

Operating system

windows 10

Additional context

No response