HTTP API: Deprecate WP_Http_Curl and WP_Http_Streams classes.

These classes have not been used in WordPress Core since the Requests library was introduced in [37428]. These classes are now deprecated in favor of `WP_Http`.

There are two remaining spots in Core that reference these classes:
- The `WP_Http::_dispatch_request()` method, which was marked as deprecated in favor of `WP_Http::request()` in [42766]/[44346].
- The `WP_Http::_get_first_available_transport()`.

That latter is now also marked as deprecated in favor of `\WpOrg\Requests\Requests::get_transport_class()`.

Props SergeyBiryukov, rajinsharwar, hellofromTonya.
Fixes #58705.

git-svn-id: https://develop.svn.wordpress.org/trunk@56655 602fd350-edb4-49c9-b593-d223f7449a82

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

@@ -15,6 +15,8 @@
  * Requires the Curl extension to be installed.
  *
  * @since 2.7.0
+ * @deprecated 6.4.0 Use WP_Http
+ * @see WP_Http
  */
 #[AllowDynamicProperties]
 class WP_Http_Curl {

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

@@ -12,6 +12,8 @@
  *
  * @since 2.7.0
  * @since 3.7.0 Combined with the fsockopen transport and switched to `stream_socket_client()`.
+ * @deprecated 6.4.0 Use WP_Http
+ * @see WP_Http
  */
 #[AllowDynamicProperties]
 class WP_Http_Streams {

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

@@ -516,6 +516,8 @@ class WP_Http {
 	 * Tests which transports are capable of supporting the request.
 	 *
 	 * @since 3.2.0
+	 * @deprecated 6.4.0 Use WpOrg\Requests\Requests::get_transport_class()
+	 * @see WpOrg\Requests\Requests::get_transport_class()
 	 *
 	 * @param array  $args Request arguments.
 	 * @param string $url  URL to request.