Display re-authentication message on boards when required

Summary

When SAML re-authentication is needed, the user is presented with an empty board and no message indicating the problem. We should display a message informing the user that they need to re-authenticate in order to load the content.

Original issue content

It has been probably months we struggle with this problem. That is why we abandoned GitLab's issue tracker for a while.

Recently, I've decided to give it one more try, and we still face the same issues.

Almost daily, when I open my board it is completely empty. You can the see the counter of issues for each column is not zero, but not issues are displayed at all.

There are no filters applied. It is needed to clear the browser's cache in order to get it back to life.

I've checked the network responses, and it seems none of them return the actual issues.

That is sad. We've opened our Github account and enrolled our developers. We are considering abandoning GitLab because of these problems.

Empty board screenshot