External Libraries: Fix PHP 7.4 compatibility issue in the Requests library.

Moves https://github.com/rmccue/Requests/pull/370 into WordPress.

Previous [46258].

See #47746.


git-svn-id: https://develop.svn.wordpress.org/trunk@46416 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/Requests/Cookie.php

@@ -288,6 +288,11 @@ class Requests_Cookie {
 				return $expiry_time;
 
 			case 'domain':
+				// Domains are not required as per RFC 6265 section 5.2.3
+				if (empty($value)) {
+					return null;
+				}
+
 				// Domain normalization, as per RFC 6265 section 5.2.3
 				if ($value[0] === '.') {
 					$value = substr($value, 1);