Lens: Add an option to change the legend height when the legend is at the top or bottom.

[TinaHeiligers]

Describe the feature:
There should also be an option to adjust the legend height for a lens vis when choosing a top or bottom position.

For example:
One can adjust the legend width for a right/left position:

But there isn't an option for a legend displayed on the top or bottom.

This leaves an awful lot of whitespace which is undesirable in a Dashboard.

Note: The stack version here is 8.3 (from snapshot), on cloud dev region using Firefox 101.0 as a browser.

[elasticmachine]

Pinging @elastic/datavis (Feature:ElasticCharts)

[elasticmachine]

Pinging @elastic/kibana-vis-editors @elastic/kibana-vis-editors-external (Team:VisEditors)

[TinaHeiligers]

@flash1293 I didn't feel comfortable fitting this issue into your Meta enhancements issue description. Would you mind adding it accordingly?
Thanks!

[sorenlouv]

I created a similar feature request (#168313).

This leaves an awful lot of whitespace which is undesirable in a Dashboard.

My use case was the opposite, in that I'd like to get rid of the scrollbar and increase the size of the legend height.

[timductive]

This will likely be improved when we do the legend redesign elastic/elastic-charts#2096

[mbondyra]

This is partially solved as the space is not bigger as the elements inside:

But the height is not modifiable. Not planning for now so iceboxing.