Notebooks with names that differ only in special characters are merged (MD export)

Export of the following folders
![grafik](https://github.com/JackGruber/joplin-plugin-backup/assets/24863925/ca7833a0-81ad-4180-a05b-904b9f5756c6)
end in the folowing file/folder structure 
![grafik](https://github.com/JackGruber/joplin-plugin-backup/assets/24863925/99488e4f-f50c-4eab-ad81-79e158dde4ba)

Open Bug report https://github.com/laurent22/joplin/issues/9436