QueryEditor: Improve support for query editors when changing data source type

[mckn]

What happened:
During the work with #60218 I saw that we have duplicated logic for how to create and change queries. We have some logic used by alerting and some other logic being used by the dashboards/panel edit.

Currently, in alerting, we are not supporting changing data source properly. We keep some of the values in the query model even if you change to a data source of a completely different type. This can cause the query editor to break or behave unexpectedly.

What you expected to happen:
I think it would be a good idea to align the logic for creating and clearing queries when changing data sources or adding a new query. We should also apply the default values provided by the data source when clearing/adding queries.

References:

• Datasource: Fix - apply default query also to queries in new panels #59625 (How to get defaults from a DS)
• https://github.com/grafana/grafana/blob/main/public/app/features/alerting/unified/components/rule-editor/QueryRows.tsx#L62
• https://github.com/grafana/grafana/blob/main/public/app/features/alerting/unified/components/rule-editor/query-and-alert-condition/reducer.ts#L59

[soniaAguilarPeiron]

should we close this one? I think this was fixed in this PR (see description)

[gillesdemey]

Correct, closing this one