More detailed error message when user has no access

[edlerd]

Done

• More detailed error message when user has no access to a project or the project is not found.

Fixes #783

QA

1. Run the LXD-UI:
   • On the demo server via the link posted by @webteam-app below. This is only available for PRs created by collaborators of the repo. Ask @mas-who or @edlerd for access.
   • With a local copy of this branch, run as described here.
2. Perform the following QA steps:
   • Use restricted user (see Restricted projects goes to /ui/project/default and print 404 #783 for commands) with no projects to access the ui
   • Ensure with granted permissions, the ui is still behaving normal on first load of the root and other urls

Screenshots

[webteam-app]

Demo

Jenkins

demos.haus

[mas-who]

LGTM, thanks for the improvement 👍

@edlerd I was able to replicate the issue reported in #783 with the --project flag that's missing the 's'. So I don't think there is a bug. Although maybe we should disable the project selector when no projects are returned by the server? Just a suggestion, not critical for this PR.

[edlerd]

@edlerd I was able to replicate the issue reported in #783 with the --project flag that's missing the 's'. So I don't think there is a bug. Although maybe we should disable the project selector when no projects are returned by the server? Just a suggestion, not critical for this PR.

I was thinking about the project selector, but didn't have a good idea how to improve it in the "no project access" case -- hence I left it as it was.