Access paramater in onStart method in the partial

Variables passed in parameter partils not accessed in onStart method in the partial.

With merged vars before render partial, stays like this::

```php
function onStart() {
   $this['param'];
}
```

modules/cms/classes/Controller.php

@@ -753,7 +753,7 @@ class Controller
     public function renderPartial($name, $parameters = [], $throwException = true)
     {
         $vars = $this->vars;
-
+        $this->vars = array_merge($this->vars, $parameters);
         /*
          * Alias @ symbol for ::
          */