[Search:AppSearch:Users and roles page]Engine assignment group is skipped when navigating with the keyboard

[L1nBra]

Description
Navigation between two radio groups should be clear and easy. User should be able to move easily from one group to another.

Preconditions
Stateful App Search -> Users and roles page is opened.
Engine is added.

Steps to reproduce

1.Navigate to Create a new role mapping button by pressing Tab key.
2.Press Enter.
3.Navigate to Role group by pressing Tab key.
4.Navigate to Dev radio button pressing down arrow key.
5.Press Tab key.
6.Observe Create a role mapping flyout.

UI elements
Role mapping flyout

New user flyout

Actual Result

• Engine assignment group is enabled, when user press Tab key - navigation goes directly to combo box field which belongs to Assign to specific engine radio button.
  Similar behavior when adding an existing user.

Expected Result

• After pressing Tab, focus goes to Engine assignment group checked radio button (Assign to specific engines).

Notes:
It is possible to navigate from Owner radio button to Assign to specific engines radio button while pressing down arrow key. Focus moves to the next radio button and checks it. After Analyst radio button when user press down arrow key, focus shouldn't go to Engine assignment radio group.

In this case if user would want a combination of Dev and Assign to all engines radio buttons, when on Dev user should press Tab key, then Esc key to close combo box options, then Shift + Tab key to move to Assign to specific engines radio button, then up arrow key to finally reach Assign to all engines radio button.

Meta Issue

Kibana Version: 8.17.0-SNAPSHOT

OS: Windows 11 Pro

Browser: Chrome Version 130.0.6723.70 (Official Build) (64-bit)

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)
• Understanding SC 1.3.1: Info and Relationships (Level A)(https://www.w3.org/WAI/WCAG22/Understanding/info-and-relationships.html)
• Understanding SC 2.4.3: Focus Order (Level A)(https://www.w3.org/WAI/WCAG22/Understanding/focus-order.html)

Related to: https://github.com/elastic/search-team/issues/8256

[elasticmachine]

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