list/hostgroups: Preserve filter when switching to grid mode

refs #3664

modules/monitoring/application/views/scripts/list/hostgroups.phtml

@@ -8,7 +8,7 @@ if (! $this->compact): ?>
     <div class="sort-controls-container">
         <?= $this->limiter ?>
         <?= $this->sortBox ?>
-        <a href="<?= $this->href('monitoring/list/hostgroup-grid') ?>" class="grid-toggle-link"
+        <a href="<?= $this->href('monitoring/list/hostgroup-grid')->addFilter($this->filterEditor->getFilter()) ?>" class="grid-toggle-link"
            title="<?= $this->translate('Toogle grid view mode') ?>">
             <?= $this->icon('th-list', null, ['class' => '-active']) ?>
             <?= $this->icon('th-thumb-empty', null, ['class' => '-inactive']) ?>