Restoring a version leads to a file conclict that remains unnoticed in read only mode

[juliusknorr]

This was reported today in chat, filing so we don't forget about it:

• Have a page where the content is removed in text/collectives
• Restore the previous version from the sidebar
• Open the collectives page in readonly

Actual

The read only view is rendered empty

Expected

The read only view should render the file content

Additional context

The fix is probably something to happen in text, but I think it is mainly noticed in collectives due to the read only mode. Related to nextcloud/text#4078