Add backwards compatibility for query variables referencing themselves

[oscarkilhed]

There are some old dashboards that have query variables that reference themself in the query, this is preventing the query runner from executing the variable query as it is waiting for the variable to load.

I'm not confident this is the best solution to this issue. A different approach would be to remove the reference to itself when we build the scene, however this could potentially be quite messy. We should probably also look into if this is an issue with other variable types.

https://github.com/grafana/support-escalations/issues/11766

[ivanortegaalba]

Tests are breaking too

[ivanortegaalba]

Tests fixed!

[grafanabot]

:rocket: PR was released in v5.7.4 :rocket: