HTTP API: Deprecate the http_api_transports filter.

The filter is only used within the `WP_Http::_get_first_available_transport()` method, which has been marked as deprecated in favor of `\WpOrg\Requests\Requests::get_transport_class()`.

Follow-up to [56655]

Props desrosj, hellofromTonya.
Fixes #58705.

git-svn-id: https://develop.svn.wordpress.org/trunk@56723 602fd350-edb4-49c9-b593-d223f7449a82

Author: SergeyBiryukov

src/wp-includes/class-wp-http.php

@@ -531,13 +531,14 @@ public function _get_first_available_transport( $args, $url = null ) {
 		 * Filters which HTTP transports are available and in what order.
 		 *
 		 * @since 3.7.0
+		 * @deprecated 6.4.0 Use WpOrg\Requests\Requests::get_transport_class()
 		 *
 		 * @param string[] $transports Array of HTTP transports to check. Default array contains
 		 *                             'curl' and 'streams', in that order.
 		 * @param array    $args       HTTP request arguments.
 		 * @param string   $url        The URL to request.
 		 */
-		$request_order = apply_filters( 'http_api_transports', $transports, $args, $url );
+		$request_order = apply_filters_deprecated( 'http_api_transports', array( $transports, $args, $url ), '6.4.0' );
 
 		// Loop over each transport on each HTTP request looking for one which will serve this request's needs.
 		foreach ( $request_order as $transport ) {