Show error description in list and details view

We are only showing the error name in the UI, making it hard to understand what the error is about.

We should add the error description as well, since it's already fetched by the UI. It's just a matter of displaying it somewhere.

e.g.

For https://gitlab.com/gitlab-org/opstrace/tryout-error-tracking/-/error_tracking/1214356540/details

We only show *url.Error

but we are not showing the error description, "Get "fake-url": unsupported protocol scheme """