fix(legacy): do not delete audio file when removing artwork

[togir2]

Description

While removing a custom artwork the audio file is also deleted.

This is a new feature:

No

I have updated the documentation to reflect these changes:
No

Testing Notes

This bug does only appear with custom cover images.
The default ones are not affected because they are in a different folder than the custom ones

1. Edit track
2. Add custom cover image and save
3. remove cover image => audio_file deleted

After the patch:

1. Edit track
2. Add custom cover image and save
3. remove cover image => audio_file is not deleted

[jooola]

Ooh, nice catch!

Now that I see this, the glob really scares me. I think we should be more explicit to what we delete here.

I've pushed an extra commit to replace the glob and fixed the CI checks.

Thanks for the patch!