Validates the logged-in cookie.

Checks the logged-in cookie if the previous auth cookie could not be
validated and parsed.

This is a callback for the {@see ‘determine_current_user’} filter, rather than API.

function wp_validate_logged_in_cookie( $user_id ) {
	if ( $user_id ) {
		return $user_id;
	}

	if ( is_blog_admin() || is_network_admin() || empty( $_COOKIE[ LOGGED_IN_COOKIE ] ) ) {
		return false;
	}

	return wp_validate_auth_cookie( $_COOKIE[ LOGGED_IN_COOKIE ], 'logged_in' );
}