MDL-73811 reportbuilder: ensure audience cards are uniquely keyed.

reportbuilder/classes/local/helpers/audience.php

@@ -214,9 +214,11 @@ class audience {
         $notavailablestr = get_string('notavailable', 'moodle');
 
         $audiencetypes = self::get_audience_types();
+        $audiencetypeindex = 0;
         foreach ($audiencetypes as $categoryname => $audience) {
             $menucards = [
                 'name' => $categoryname,
+                'key' => 'index' . ++$audiencetypeindex,
             ];
 
             foreach ($audience as $classname => $name) {

reportbuilder/templates/local/sidebar-menu/card.mustache

@@ -22,6 +22,7 @@
     Example context (json):
     {
         "name": "General",
+        "key": "general",
         "items": [{
             "name": "Manually added users",
             "identifier": "core_reportbuilder:users"