[Observability:AIassistant] Set up GenAI connector panel and different AI connector config panel is incorrectly announced

[bhavyarm]

Description
When user clicks on set up GenAI connector panel and or on different genAI connectors from this connector, Kibana announces the opening of the panels incorrectly without giving any context to user.

Preconditions
Observability->Ai assistant

Steps to reproduce

1. Navigate observability->AIassistant
2. Use voiceover on the page
3. Click on set up GenAI connector panel
4. Notice Kibana announcing the opening with a very generic EUI message about a modal dialog without giving the user any context about them opening the panel for setting up GenAI connectors
5. Same bug when user clicks on individual genAI connector

Kibana Version: 8.18.0

OS: OS X

Browser: Chrome latest

"Screenreader:* Voiceover

WCAG or Vendor Guidance (optional)

• Understanding SC 4.1.2: Name, Role, Value (Level A)(https://www.w3.org/WAI/WCAG22/Understanding/name-role-value.html)

Related to: https://github.com/elastic/kibana-team/issues/1254

[elasticmachine]

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

[bhavyarm]

From Lene:

The component supports passing aria-label or aria-labelledby to provide a proper name for the dialog, but that needs to be done on implementation side.
On EUI side what's being done is that we add a aria-describeby which adds the help text You are in a modal dialog. Press Escape or tap/click outside the dialog on the shadowed overlay to close