Plugin: Only override REST server for older WP versions

[Mamaduka]

What?

PR makes REST server override conditional and only applies it WP < 6.7. There's no need to override if WP already supports targetHints.

How?

Uses the get_user function for version check. This is more efficient than version checks.

Testing Instructions

None. Just confirm that the logic is correct.

Testing Instructions for Keyboard

Same.

[github-actions]

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Co-authored-by: Mamaduka <mamaduka@git.wordpress.org>
Co-authored-by: gziolo <gziolo@git.wordpress.org>

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[github-actions]

Flaky tests detected in 4a3d821.
Some tests passed with failed attempts. The failures may not be related to this commit but are still reported for visibility. See the documentation for more information.

🔍 Workflow run URL: https://github.com/WordPress/gutenberg/actions/runs/12251410614
📝 Reported issues:

• [Flaky Test] submenu click on the arrow interactions #61884 in /test/e2e/specs/editor/blocks/navigation-frontend-interactivity.spec.js