refactor: convert FieldValueToggleFilter to function component

[CollegeRideOut]

Summary

Convert FieldValueToggleFilter from a class component to a stateless function component.

• Refactored to use FC<FieldValueToggleFilterProps> style
• Stateless render-only; no functional changes
• Prettier formatting applied

API Changes

None — this is an internal component and its API hasn’t changed.

Screenshots

Not applicable — no visual changes.

Impact Assessment

• 🔴 Breaking changes — None
• 💅 Visual changes — None
• 🧪 Test impact — All existing tests pass
• 🔧 Hard to integrate — N/A

Impact level: 🟢 None

Release Readiness

• Documentation — N/A
• Figma — N/A
• Migration guide — N/A
• Adoption plan — N/A

QA instructions for reviewer

• Verify the FieldValueToggleFilter behaves as before in Storybook and any demo pages
• Confirm that toggling the filter updates the query as expected

Checklist before marking Ready for Review

• Filled out all sections above
• QA: Verified light/dark mode, accessibility, keyboard navigation
• Tests: Existing Jest/Cypress tests pass
• Changelog: Not needed (internal component)
• Breaking changes: None

[cla-checker-service]

💚 CLA has been signed

[github-actions]

👋 Since this is a community submitted pull request, a Buildkite build has not been started automatically. Would an Elastic organization member please verify the contents of this pull request and kick off a build manually?

[weronikaolejniczak]

buildkite test this

[Copilot]

Pull request overview

This PR refactors the internal FieldValueToggleFilter search bar filter from a class component to a stateless function component, aiming to keep behavior the same while modernizing the implementation.

Changes:

• Converted FieldValueToggleFilter from Component to FC<FieldValueToggleFilterProps>.
• Moved class methods (resolveDisplay, valueChanged) to local arrow functions within the function component.
• Applied formatting updates (though a few formatting/style issues remain in the diff).

Comments suppressed due to low confidence (1)

packages/eui/src/components/search_bar/filters/field_value_toggle_filter.tsx:78

• The component export ends with } instead of };, and there are multiple trailing blank lines at EOF. Please run prettier/formatting (or manually adjust) to match the conventions in other filters (single newline at EOF, semicolons where expected).

  );
}

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[elasticmachine]

💚 Build Succeeded

• Buildkite Build
• Commit: 3e4e775
• Documentation website
• Storybook