Help/About: Fix the Get Involved tab on Network Admin.

This changeset adds a wp-admin/network/contribute.php file to allow the Get Involved tab to work on Network Admin.

Props courane01, ryelle, audrasjb.
Reviewed by joedolson.
Merges [56309] to the 6.3 branch.
See #23348.

git-svn-id: https://develop.svn.wordpress.org/branches/6.3@56310 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/network/contribute.php

@@ -0,0 +1,13 @@
+<?php
+/**
+ * Network Contribute administration panel.
+ *
+ * @package WordPress
+ * @subpackage Multisite
+ * @since 6.3.0
+ */
+
+/** Load WordPress Administration Bootstrap */
+require_once __DIR__ . '/admin.php';
+
+require ABSPATH . 'wp-admin/contribute.php';