[EuiDataGrid] Override expand behavior

[pickypg]

Relates to #2793.

I would like the ability to display a Flyout (with an overlay mask) or a Modal (also with the mask) when the user selects the expand button so that I can force them to do something with it or to discard it without having the chance to do anything else with the grid, particularly since I cannot disable the grid while the detail view is visible.

[github-actions]

👋 Hey there. This issue hasn't had any activity for 180 days. We'll automatically close it if that trend continues for another week. If you feel this issue is still valid and needs attention please let us know with a comment.

[pickypg]

I do not know if this works or not given all of the changes to the Data Grid since this was written. I think it's useful, but I'm going to close it under the assumption that it works now.