Public dashboard link still accessible after the dashboard is archived

[madalincm]

Steps to Reproduce:

1. Create a new dashboard
2. Add a visualization widget and a text widget to it
3. Generate a public link for the dashboard. Make a copy of this link
4. Archive the dashboard
5. Open the link generated in step 3 in a new window

Expected results:

The link should no longer be accessible.

Actual results:

The link is accessible. All the information from the archived dashboard can be seen using the generated public link.

Notes/Issues:

Build identifier: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0
Verified in FF58(Win7). Issue can be reproduced in STMO-stage
Link for the archived dashboard: https://pipeline-sql.stage.mozaws.net/dashboard/testarchived?page=1
Public link: https://pipeline-sql.stage.mozaws.net/public/dashboards/Ts0wecKqrOCsLAOD92rkDc5ydXXbI0MAtU0GhW1h?org_slug=default

[rafrombrc]

Hrm. Yeah, this is a bit weird, bc since redash has no 'delete query' function, this effectively means it's impossible to make a public query no longer available. Maybe we should be showing that the query has been archived instead of the results?