[Lens] Show indication that there is data in bar charts when the y-axis is very large

[teresaalvarezsoler]

Problem When the y-axis is has a very large scale, bars don't appear for very low numbers as shown in this picture:

Solution We should at least show a fine line when y-axis values >0

[elasticmachine]

Pinging @elastic/kibana-visualizations (Team:Visualizations)

[markov00]

possible solution: use the chart minBarHeight property to give the bar a min height of 1 or 2 px

[nickofthyme]

@teresaalvarezsoler isn't this discover? We already have the minBarHeight applied since https://github.com/elastic/kibana/pull/168644.