Static size for stacked bar charts

[M-Louw]

Describe the feature:
Right now (Kibana 7.5), the size option for a stacked bar chart returns the size * buckets. I would like to be able to set a static size, so I always know how many bars I show in my chart, and the size of the bar chart does not change based on filters I make.

Describe a specific use case for the feature:
A Top 10 visualisation.
Say we have 100 gardens.
I want to see the top 10 gardens based on the sum of all the fruit trees. This will give me 10 bars where each bucket is a fruit tree, and I can see the ten gardens that have the most trees overall.
When filtering on "Apple trees" I still want to see Top 10, but now only for the gardens who has apple trees.

Community post: https://discuss.elastic.co/t/horizontal-barchart-size/223479

[elasticmachine]

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

[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