Infinite spinner when trying to open a non-existent design
Summary
When following a deep link to the non-existent/deleted design, the infinite loading spinner is shown instead of error message
Steps to reproduce
Try to open https://gitlab.com/gitlab-org/growth/product/-/issues/1520/designs/Usage_quota_storage_-_iteration.jpg#note_319385397
or a link with the wrong design filename. You will see an infinite spinner instead of error message
What is the current bug behavior?
When opening a non-existent MR, an infinite spinner is shown
What is the expected correct behavior?
We should show a correct error message notifying the user about non-existent design.
This bug reproduces on GitLab.com
Edited by Tom Quirk