External people can't open documents in read-write mode

[schiessle]

Observed at c.cn.com (Nextcloud 23.0.0.10)

Steps to reproduce

1. Share a folder with a office document as public link
2. Set permissions to "can edit"
3. Open the link in a browser window where you are not logged in

Result

document can't be opnened

If I remove the "can edit" open, Collabora Online can open the file in read-only mode.

Expected

external user can open the document and edit it

[juliusknorr]

Already tracked in nextcloud/richdocuments#1914

I've also introduced a link to the repository when creating issues here as this repo is mainly for office team coordination.