[Search:Playground page]Total number of options announced before each option

[L1nBra]

Description
It is enough for the user to hear total number of options then he/she firstly reaches the field which has options.

Preconditions
Stateful Playground page is opened.
Use Screen Reader (NVDA).

Steps to reproduce

1.Navigate to Connect to an LLM button by pressing Tab key.
2.Press Enter.
3.Navigate to AI connector button by pressing Tab key.
4.Press Enter.
5.Navigate to Service field by pressing Tab key.
6.Press Enter.
7.Navigate through the options with arrow keys.
8.Observe screen reader.

NVDA Speech Viewer +UI elements

Actual Result

• Total number of options is announced before each option.

Expected Result

• Total number is announced only when user firstly navigates to the field and presses Enter on it (not before each option).

Meta Issue

Kibana Version: 8.17.0-SNAPSHOT

OS: Windows 11 Pro

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

Screen reader: NVDA

WCAG or Vendor Guidance (optional)

• Understanding SC 1.3.1: Info and Relationships (Level A)(https://www.w3.org/WAI/WCAG22/Understanding/info-and-relationships.html)
• 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/search-team/issues/8256

[elasticmachine]

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