(Accessibility) Retest visualization builders for screen reader interactivity with drag and drop interface

[1Copenut]

Description
Spike ticket to test two visualization builder types with screen readers. Looking specifically at the drag and drop interfaces in the following items:

1. Markdown panel builder (from dashboard). Can we drag the two resizable containers with all screen readers and their preferred pairings?
2. TSVB visualization builder. Can we drag and drop data points from the left menu to the main drop zone in the middle?

[elasticmachine]

Pinging @elastic/kibana-accessibility (Project:Accessibility)

[elasticmachine]

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

[drewdaemon]

@1Copenut I see that you've tagged the visualizations team. Are you asking us to perform this spike? If so, the markdown panel is owned by the presentation team, so perhaps we could split up this issue?

[elasticmachine]

Pinging @elastic/kibana-presentation (Team:Presentation)

[1Copenut]

I see that you've tagged the visualizations team. Are you asking us to perform this spike? If so, the markdown panel is owned by the presentation team, so perhaps we could split up this issue?

@drewdaemon No, I'll have to retest these. I had a request come in for testing with NVDA / JAWS and didn't have access to the equipment at the time (do now). When I opened the spike ticket it didn't have a team and got assigned to Visualizations based on the description.