fix: [security] Fixed stored xss when exporting custom clusters into the misp-galaxy format

- As reported by fukusuket (Fukusuke Takahashi)

Author: mokaddem

Diff for: app/View/GalaxyClusters/cluster_export_misp_galaxy.ctp

@@ -5,7 +5,7 @@
         <p>This JSON can be added added to the <code class="quickSelect">misp-galaxy/clusters/<?= h($cluster['GalaxyCluster']['type']) ?>.json</code>.</p>
         <p>Don't forget to bump the <code>version</code> specified at the end of the <code><?= h($cluster['GalaxyCluster']['type']) ?>.json</code> file.</p>
 
-        <pre class="quickSelect"><?= JsonTool::encode($convertedCluster, true) ?></pre>
+        <pre class="quickSelect"><?= JsonTool::encode(h($convertedCluster), true) ?></pre>
     </div>
 </div>
 <?= $this->element('/genericElements/SideMenu/side_menu', ['menuList' => 'galaxies', 'menuItem' => 'view_cluster']);