Don't override login template in collection controller.

module/VuFind/src/VuFind/Controller/CollectionController.php

@@ -87,7 +87,9 @@ class CollectionController extends AbstractRecord
         }
 
         $result = parent::showTab($tab, $ajax);
-        if (!$ajax && $result instanceof \Laminas\View\Model\ViewModel) {
+        if (!$ajax && $result instanceof \Laminas\View\Model\ViewModel
+            && $result->getTemplate() !== 'myresearch/login'
+        ) {
             $result->setTemplate('collection/view');
         }
         return $result;