Allow all embeddables to display description in Dashboard panel

[nreese]

#44702 added a neat feature where users can save descriptions with their visualizations and then those descriptions are available on dashboards. This is a great way to provide context for panels in dashboards.

The problem is that the implementation is Visualization embeddable specific.

https://github.com/elastic/kibana/blob/master/src/plugins/embeddable/public/lib/panel/panel_header/panel_header.tsx#L71

function getViewDescription(embeddable: IEmbeddable | VisualizeEmbeddable) {
  if (embeddable.type === VISUALIZE_EMBEDDABLE_TYPE) {
    const description = embeddable.getVisualizationDescription();

    if (description) {
      return description;
    }
  }

  return '';
}

The Maps app would like to provide the some type of functionality so users can provide context for maps when they are embedded in Dashboards, or any where else.

It would be great if getViewDescription would work for any embeddable and just use something more generic like embeddable.getDescription()

cc @stacey-gammon @elastic/kibana-gis @streamich @friol

[elasticmachine]

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

[stacey-gammon]

I'm pretty sure we can make this feature generic by putting description on output, then using embeddable.getOutput().description. If you want to expose a way to edit it via panel actions it should be on input. That would probably be better, but if you always want the description that is with the saved object, I think output is the spot for it.

[timroes]

Related to #2538

I think if we implement the dashboard help texts, we should just use the description of the visualization as a default value (basically the same as we currently do for the panel title and vis title).

[nreese]

Closed by #78767