[Lens][Datatable] Follow up on column actions after EUI 95 upgrade

[dej611]

From @cee-chen comment here:

Yep, I removed .euiDataGridHeader__action--selected from our classNames/CSS as it wasn't actually applying any useful styles anymore, and I hadn't realized this FTR test was hooking into it 😬 I replaced it instead with logic that adds "Sort/Unsort" text to represent currently sorted state:

But it looks like the Lens datagrid completely overrides the sort label with your own Sort ascending/descending node, which means that the default "Unsort" text can't be hooked into.

Options I can look into:

Remove your label override with a schemaLabel instead, which means that you get EuiDataGrid's "Unsort" text (the schemaLabel replaces the A-Z/Z-A text only)
Re-add a selected state as a data- attribute of some kind that you can hook into (would likely be the next release, and I can revert the Lens changes at that point)

[elasticmachine]

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

[cee-chen]

It's still not clear to me what the ask is, but if y'all have one specifically please let me know if I can help.

To clarify also, these changes only applied to test utilities and not to source code.