Can't initialize plugin when multiple Loki datasources are present

[ckbedwell]

What happened: In my set-up I have two Loki datasources set-up in my provisioning file. If I don't have an SM datasource and try to initialise the plugin, nothing happens.

What you expected to happen: I would expect something like: a) feedback that the plugin was unable to initialise, why and how to fix the issue b) the app initialises correctly by self-correcting c) potentially offered a choice of which datasource to use? (this might not be possible)

How to reproduce it (as minimally and precisely as possible): Add an extra Loki datasource to your provisioning file with the uid: grafanacloud-logs, which is not the datasource that your app provisioning file's Loki datasource is referencing.

Anything else we need to know?: A lot of this logic was added in a PR last year which seems to relate to ensuring the solution works for cloud and on-prem solutions: https://github.com/grafana/synthetic-monitoring-app/pull/552, please take this into account when creating a solution.

Related issue: https://github.com/grafana/synthetic-monitoring-app/issues/844