Image placeholder shows wrong image when diagram is restricted

[mararad]

When user enters page editor on a page that contains diagrams with restricted access (linked from a restricted page from example), macro placeholder shows an informative image, draw.io logo with "403 - access denied" message.

This does not work when collaboration mode is on. Placeholder instead shows a broken image.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions. See the FAQ for more information.