[Lens] Enable missing values option for percentage stack area charts as well

[dej611]

In Lens the Percentage Area charts do not support the "Missing values" feature, probably due to initial lack of support in the elastic-charts library.

I've asked @nickofthyme and he confirmed that the library now supports the feature (see link ), therefore it is technically possible to enable it.

Before the actual implementation may be worth to discuss about it (cc @markov00 @flash1293 )

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[wylieconlon]

I am definitely in favor of supporting this feature for area and stacked area charts. I wonder if we should actually set a default fitting function of Zero for these charts because the way that stacked area charts render is problematic without this. The data in the screenshots is random, so it's not a direct comparison of the data, but just the aesthetic:

Current default with holes:

The new default I'm proposing for Area charts, Zero fitting function:

[dej611]

The Zero setting is current default for Area percentage charts.
Not sure whether it makes sense to add more options, but in case we want to add it, probably we should reset to default fit when transitioning to Area Percentage mode. WDYT?

[markov00]

In order to provide better transparency of priorities, issues that will not be prioritized within the next 24 months are being closed.

Tracking request in Lens general improvements ice box #184459