MIDI channels sometimes contain more than one instrument types even when there are less instruments than channels

Issue type

Import/export issue

Bug description

Whenever I try to export to MIDI I sometimes get a problem where multiple tracks use the same instrument type even though they don't have the same instrument type in Musescore. In a MIDI I exported with the list of instruments below, the piano, harpsichord, oboe and a few other samples ended up sounding like strings. I think this has something to do with pizzicato and tremolo channels being overlapped with other channels. I seem to have this issue with most scores with a couple of String instruments like violins, celli, basses, etc.

Also, in a music xml export, with the instruments in the screenshot, the harpsichord and the cello end up on the same MIDI channel.

Steps to reproduce

1. Open a file that has about 10 instruments including a string quintet, electric guitar, bass or some FX synths,
2. Export to MIDI
3. Sometimes a track meant to be played by a specific instrument will be played by another instrument.

Screenshots/Screen recordings

No response

MuseScore Version

Musescore 4 and above

Regression

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

Operating system

Windows 10

Additional context

musicxml_extract.txt

Start with the attached musicxml_extract.txt and reproduce the issue using a score with about 10 instruments, including strings, then export it to MIDI and MusicXML. Compare the resulting channel and instrument assignments with the MuseScore score; done means distinct intended instruments remain distinct in both exports.