HTTP API: Ensure value returned from 'http_allowed_safe_ports' is an array to avoid PHP 8+ TypeError fatal error.

Adds an `is_array()` check before the `in_array()`. Why? `in_array()` requires a array for the haystack. Any other data type will cause a fatal error on PHP 8.0 or higher:

{{{
Fatal error: Uncaught TypeError: in_array(): Argument #2 ($haystack) must be of type array
}}}

As this is a new filter, this type check properly guards to avoid the fatal error.

Follow-up to [52084].

See #54331.

git-svn-id: https://develop.svn.wordpress.org/trunk@52085 602fd350-edb4-49c9-b593-d223f7449a82

Author: hellofromtonya

src/wp-includes/http.php

@@ -593,7 +593,7 @@ function wp_http_validate_url( $url ) {
 	 * @param string $url           Requested URL.
 	 */
 	$allowed_ports = apply_filters( 'http_allowed_safe_ports', array( 80, 443, 8080 ), $host, $url );
-	if ( in_array( $port, $allowed_ports, true ) ) {
+	if ( is_array( $allowed_ports ) && in_array( $port, $allowed_ports, true ) ) {
 		return $url;
 	}