MDL-76867 core: Add plugintype_supports_disabling to plugininfo

lib/classes/plugininfo/mod.php

@@ -31,6 +31,11 @@ use part_of_admin_tree;
  * Class for activity modules
  */
 class mod extends base {
+
+    public static function plugintype_supports_disabling(): bool {
+        return true;
+    }
+
     /**
      * Finds all enabled plugins, the result may include missing plugins.
      * @return array|null of enabled plugins $pluginname=>$pluginname, null means unknown