Improves screen reader features of combo boxes in edit role screen

[jeramysoucy]

Summary

Related to #27749

While the EuiComboBox rebuild is in progress, this PR addresses missing aria properties and fixes option announcements for the run as user combo. It additionally adds an aria-label for the Spaces Navigation EuiSelectable that I found was missing.

Testing

• Add all sample data
• Edit a non-reserved role
• Turn on a screen reader (NVDA is recommended, but VoiceOver will do)
• Tab through the controls on the Edit role screen. When you arrive in a combo box you may or may not hear an announcement declaring the name of the combo box (this is expected, especially with VoiceOver).
• With focus in a combo box press the down arrow key. Verify the options are announced as you traverse them with the down and up arrow keys.
• If there was success in option announcement, press escape key and verify that the name of the combo box is announced. You may have to press escape twice when using NVDA.

Note: It seems to be the consensus that this is best we can do with the existing implementation of EuiComboBox, which is partly why it is being rebuilt with the EuiSelectable component.

[elasticmachine]

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

[kc13greiner]

Just a couple questions to help me understand!

[kc13greiner]

LGTM! Thanks for the info!

[kibana-ci]

💛 Build succeeded, but was flaky

• Buildkite Build
• Commit: be7af74

Failed CI Steps

• FTR Configs #13

Test Failures

• [job] [logs] FTR Configs #13 / dashboard dashboard maps by value editing a map and adding to map library updates the existing panel when adding to dashboard
• [job] [logs] FTR Configs #13 / dashboard dashboard maps by value editing a map by value "before all" hook for "retains the same number of panels"

Metrics [docs]

Async chunks

Total size of all lazy-loaded chunks that will be downloaded as the user navigates the app

id	before	after	diff
security	557.1KB	557.3KB	+189.0B
spaces	174.6KB	174.7KB	+97.0B
total			+286.0B

Unknown metric groups

ESLint disabled line counts

id	before	after	diff
securitySolution	433	436	+3

Total ESLint disabled count

id	before	after	diff
securitySolution	513	516	+3

History

• 💔 Build #116769 failed 9dfdd15
• 💚 Build #116146 succeeded d276aa3
• 💔 Build #115836 failed 25252ca
• 💔 Build #115806 failed adafdf1

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@elasticmachine merge upstream