REST API: Build oEmbed proxy URL with wp.apiRequest (#41554)

[pranav-inamdar]

Summary

Replaces localized oEmbedProxyUrl (full REST URL from PHP) with wp.apiRequest() using namespace: 'oembed/1.0' and endpoint: 'proxy', so admin embed code builds the oEmbed proxy URL consistently with other REST clients and avoids passing rest_url() output through script localization.

Follow-up to #40919; implements #41554.

Changes

• Update media embed JS to call wp.apiRequest() for oEmbed proxy previews.
• Remove the corresponding wp_localize_script / settings property from PHP (where previously passed into wp.media / related scripts).

Testing

Manual:

1. Open the media modal and use Insert from URL (not only the block editor Embed block).
2. Paste a supported URL (e.g. a YouTube watch URL) and confirm the embed preview loads.
3. In the browser Network tab, confirm the request targets the /oembed/1.0/proxy REST route (or equivalent with plain permalinks / rest_route).

Automated:

• Run relevant PHPUnit tests for the oEmbed REST proxy (e.g. tests/phpunit/tests/oembed/controller.php) in your environment.

Trac ticket: https://core.trac.wordpress.org/ticket/41554

Use of AI Tools

AI assistance: Yes
Tool(s): Cursor
Used for: Exploring the codebase, drafting and iterating on the patch, and PR description text; implementation was reviewed and adjusted manually before submission.

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