Introduce HTTP API response cookie functions

[johnbillion]

We have several HTTP API helper functions for retrieving the response code, body, and headers, but none for the cookies or an individual cookie.

Let's introduce:

• array wp_remote_retrieve_cookies( $response )
• WP_Http_Cookie wp_remote_retrieve_cookie( $response, $cookie )
• string wp_remote_retrieve_cookie_value( $response, $cookie )

[wonderboymusic]

In 34369:

HTTP: Add some new Cookie helper functions:

• wp_remote_retrieve_cookies( $response )
• wp_remote_retrieve_cookie( $response, $name )
• wp_remote_retrieve_cookie_value( $response, $name )

Adds unit tests.

Props johnbillion.
Fixes #33711.