[5.4] Convert TUF update info URL into legacy format (joomla#45980)

* Convert update infourl into legacy data format

Author: SniperSister

libraries/src/Updater/Update.php

@@ -612,10 +612,19 @@ public function loadFromTuf(TufMetadata $metadataTable, string $url, $minimumSta
 
         // If the latest item is set then we transfer it to where we want to
         if (isset($this->latest)) {
+            // Set generic variables from latest update
             foreach (get_object_vars($this->latest) as $key => $val) {
                 $this->$key = (object) ['_data' => $val];
             }
 
+            // Convert infourl into legacy data structure
+            if (!empty($this->latest->infourl) && \is_array($this->latest->infourl)) {
+                $this->infourl = (object) [
+                    '_data' => $this->latest->infourl["url"],
+                    'title' => $this->latest->infourl["title"],
+                ];
+            }
+
             foreach ($this->downloadSources as $source) {
                 $this->downloadurl = (object) [
                     '_data'  => $source->url,