[Security:Assets:Endpoints:Blocklist page]Missing error announcement for Value field

[L1nBra]

Description
When field has errors, error text has to be announced for the user, especially using assistive technology.

Preconditions
Security -> Assets -> Endpoints -> Blocklist page.
Use Screen Reader (NVDA).

Steps to reproduce

1.Navigate to Add blocklist entry button.
2.Press Enter.
3.Navigate to Value field.
4Press Tab key.
5.Press Shift + Tab keys.
6.Observe screen reader.

UI elements + NVDA Speech Viewer

Actual Result

• Field name gets red color, error text appears under the field which is not announced by screen reader. Red underline does not appear for the field.

Expected Result

• Error text is announced for the user when he/she navigates to Value field which has error. Red underline is also present.

Meta Issue

Kibana Version: 8.17.0-SNAPSHOT

OS: Windows 11 Pro

Browser: Chrome Version 131.0.6778.140 (Official Build) (64-bit)

Screen reader: NVDA

WCAG or Vendor Guidance (optional)

• Understanding SC 3.3.1: Error Identification (Level A)(https://www.w3.org/WAI/WCAG22/Understanding/error-identification.html)
• Understanding SC 1.3.1: Info and Relationships (Level A)(https://www.w3.org/WAI/WCAG22/Understanding/info-and-relationships.html)

Related to: https://github.com/elastic/kibana-team/issues/1280

[elasticmachine]

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

[elasticmachine]

Pinging @elastic/security-solution (Team: SecuritySolution)