[Obs ai assistant][ES|QL] Initial render of the ES|QL table in a more…

… compact format (elastic#190027)

## Summary

Nothing super crucial, it has to do with the initial render of the ES|QL
datable. In order to be aligned with the table we render in the flyout
and minimize the space it takes, we initialize in single row. The users
can still change the row height from the settings.

It is actually this:

<img width="1084" alt="image"
src="https://github.com/user-attachments/assets/010013fd-37a8-46ff-9847-5b004d582aca">


instead of:
<img width="1075" alt="image"
src="https://github.com/user-attachments/assets/508a0cba-d66f-434b-8136-286023c02dcc">


The users can always adapt the settings:
<img width="1117" alt="image"
src="https://github.com/user-attachments/assets/1bda9a2d-d707-43bd-8f70-571ced3b337b">

x-pack/plugins/observability_solution/observability_ai_assistant_app/public/functions/visualize_esql.tsx

@@ -353,6 +353,7 @@ export function VisualizeESQL({
                   query={{ esql: query }}
                   flyoutType="overlay"
                   isTableView
+                  initialRowHeight={0}
                 />
               ) : (
                 <lens.EmbeddableComponent
@@ -375,6 +376,7 @@ export function VisualizeESQL({
               dataView={dataViewAsync.value}
               query={{ esql: query }}
               flyoutType="overlay"
+              initialRowHeight={0}
             />
           </EuiFlexItem>
         )}