Fix: pager overwritten every time a content is loaded.

At line 2005 we need to set the global pager in twig, not just what loaded in the call.
At setPager() method the static::$pager array always exists, so we don't need extra check, just have to set the pager object indexed by $name. If the old array_key_exists at line 2945 matched true then the whole pager array overwritten with the object that was passed to the method. I don't think this check even makes sense anyway, because the static::$pager array always exists end the set line always rewrites the key/value.