TrackName in MIDI export is not using the Part Name.

Issue type

Import/export issue

Bug description

When you use custom names for the parts, it is expected that these are being used for the trackname in the MIDI export (like this was done in MS3). Instead this is not used and only the original instrument name of the part is being used in the MIDI export.

In MS3, the trackname defined for the Part was used as the trackname in the MIDI export.
In MS4, this trackname is still used however it does not contain the modified the name of the part in the MS file and therefore the resulting MIDI file does not contain the desired trackname.

Steps to reproduce

Create a new score
Add an instrument
Rename the part to a custom name
Save the score
Export the score as MIDI file
Open the MIDI file (either in another program or MS4)

Now check the name of the track/part.

Screenshots/Screen recordings

No response

MuseScore Version

4.2.1

Regression

Yes, this used to work in MuseScore 3.x and now is broken

Operating system

Windows 11

Additional context

Test.mscz.zip

Test.mid.zip

Just remove the .zip extension to get the original file (the extension is just added to allow upload to github).

The file contains a sample of a renamed part with the name: Testpartij.

Potential linked to: #19466

Reproduce the MIDI export with the attached score, renaming a part before exporting, and compare the resulting track name with the part name. Trace the MIDI export path and inspect how the part's track name is selected; done means the custom part name appears in the exported MIDI while existing exports remain correct.