[Lens] Do not run the fetch request when the user changes chart configuration

[stratoula]

Describe the feature:

Lens is architectured with that way so every time a user is making a change, the expression reruns again. This means that we are requesting the data again although the user might want to only change a color.

In dataview mode, this is fixed with the search sessions but with ES|QL this problem has been surfaced again. I would like only the expression regarding the chart configuration to run and not everything but without introducing search sessions in ES|QL.

I am labelling this as a feature request, mostly because I expect this to be a quite big change but I think that is an annoying behavior we should prioritize

[elasticmachine]

Pinging @elastic/kibana-visualizations (Team:Visualizations)

[dej611]

Can't we reuse the same memoization technique used for the autocomplete here at expression level? i.e. same query for the next 10 secs has the same result.
Of course come forcing flag would be required for some use cases.

[stratoula]

I think the best way to do it (also discussed briefly with Peter) is to not run the bsearch for this kind of changes (as we did in Discover where we are passing the datatable in the expression). We will investigate with @ppisljar but I think this is the correct path forward. In my mind this is something we need to take care holistically and not only for ES|QL. If we deprecate search sessions (are they even available in serverless?) then the dataview mode will also have problems

[stratoula]

I asked the Discovery team and search sessions are not enabled in serverless