`--score-parts` creates .json on STDOUT, not separate .mscz files as indicated by `--help` // feature request: a way to indeed create separate .mscz files

Issue type

Other type of issue

Bug description

MuseScore-4.1.1.232071203-x86_64.AppImage --help includes:
--score-parts Generate parts data for the given score and save them to separate mscz files

However, running
MuseScore-4.1.1.232071203-x86_64.AppImage --score-parts <musescore>.mscz
results in a stream to STDOUT similar to the --score-parts-pdf

The --help content indicates .mscz files will be written that are not created and the output stream is json format, not a .mscz archive format.

Steps to reproduce

MuseScore-4.1.1.232071203-x86_64.AppImage --score-parts <musescore>.mscz

results in STDOUT stream but no .mscz files created.

Screenshots/Screen recordings

No response

MuseScore Version

4.1.1.232071203

Regression

No.

Operating system

Ubuntu 22.04

Additional context

Same behavior exists in MS 3.6. --help indicates .mscz files will be created .json output on STDOUT instead.

I'm looking for a way to export PDF and MP3 for Parts from the command line in MS4. Refer to https://github.com/musescore/MuseScore/issues/19359.