[Legend] Show data series icon for filters only at hover

[gvnmagni]

I would love to consider if it is possible to hide that icon on the right side of each data series and to show it only at mouse-hover, this way we would clean up the legend from unnecessary and repetitive elements

Current state:

Suggested state:

@1Copenut any accessibility issues that we might encounter?

[nickofthyme]

Eui currently does something similar to this in the EuiDataGrid.

[1Copenut]

I'm okay making these Action menus appear on ::hover as long as they also appear on ::focus. Practically speaking it means hiding them visually until hovered or focused, then showing. I'm okay going this direction as long as we have a chance to test for keyboard and screen reader usability before the change is merged, or quickly after merge in case we need to roll back.

EuiDataGrid has this behavior, but also allows for users to press Enter to open the [ ... ] menu. That's a standard data grid interaction pattern that presents similarly for mouse interaction but is ever so nuanced for keyboard interaction.

[gvnmagni]

Thank you @1Copenut!