UI: Fix Dark and System themes select list height

UI/data/themes/Dark.qss

@@ -770,7 +770,7 @@ OBSBasicSettings {
     qproperty-advancedIcon: url(./Dark/settings/advanced.svg);
 }
 
-OBSBasicSettings QListView::item {
+OBSBasicSettings QListWidget::item {
     padding-top: 5px;
     padding-bottom: 5px;
 }

UI/data/themes/System.qss

@@ -200,7 +200,7 @@ OBSBasicSettings {
     qproperty-advancedIcon: url(:settings/images/settings/advanced.svg);
 }
 
-OBSBasicSettings QListView::item {
+OBSBasicSettings QListWidget::item {
     padding-top: 5px;
     padding-bottom: 5px;
 }