Feature Request: Remove label gap in treemap

[sslivkoff]

Hello. I have been finding plotly's treemaps very useful

One feature that I would find helpful is being able to remove the gap below each box label.

The problem is that for smaller boxes, the gap ends up taking a large amount of the space. This space is essentially wasted, and it makes each node's children proportionally smaller than they otherwise would be. This prevents an accurate visual comparison between one parent's children to another parent's children.

I have highlighted what I mean in the figure below using red arrows

Charts with lots of nesting would benefit a lot from being able to use this space