[MU4 Issue] Change to part name gets reverted after file close/open (if parts were not opened before)

Describe the bug
Modification to part name does not persist after the file is saved, closed, and reopened. It gets reverted to the default part name.

To Reproduce
Steps to reproduce the behavior:

1. Create a new score.
2. Change the name(s) of part(s).
3. Click the Parts button to verify the updated part name(s).
4. Save, close, and reopen the file.
5. Click the Parts button. Observe the part name(s) being reverted to the default.

Expected behavior
Changes to part name(s) should persist.

As a side note, the Staff/Part properties dialog box no longer contains the Part name field. Is that by design?

Platform information

• OS: Windows 11
• Build: MuseScoreNightly-223190405-master-3558138-x86_64