Spaces ComboBox in Edit Role, screen reader has quirky behavior

[jeramysoucy]

Describe the bug:

The Spaces ComboBox in the Kibana section of the Edit Role screen does not work well with a screen reader. The options in the combobox are never read when using Chrome, and are only read in Safari if at least one character has been typed into the input field of the ComboBox.

Steps to reproduce

1. Create multiple spaces
2. Navigate to Stack Management - Roles
3. Create a new role or edit a non-reserved role with no defined Kibana privileges
4. Click Add Kibana privilege
5. Turn on screen reader
6. Click into spaces combobox in Kibana privileges popover
7. Follow screen reader navigation prompts

Actual Result

• Chrome: The screen reader will never provide the available list of options or read the highlighted option
• Safari: The screen reader will only read the highlighted option after at least one character has been entered into the combobox input field (can be deleted after and it will still work until the combobox loses focus)

Expected Result

• The screen reader should read the highlighted option regardless of whether anything was typed into the combobox input

**Kibana Version: 8.4.0 (unreleased)

**OS: macOS v12.4

**Browser: Chrome & Safari (have not confirmed with Firefox or Edge)

**Screen reader: Mac VoiceOver (have not confirmed with other options)

[elasticmachine]

Pinging @elastic/kibana-security (Team:Security)

[elasticmachine]

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

[jeramysoucy]

After reviewing with the EUI team this appears to be a "browser / screen reader interop hiccup" due to the existing implementation of EuiComboBox. The EUI team is currently working on a rebuild of the EuiComboBox based on EuiSelectable.. This rebuild will resolve this issue, as well as others (#27749).

It is also worth noting that the behavior with NVDA on Windows does not include these quirks.