[gnome-games] display-view: Remove extra widget on reset

[Alexander Mikhaylenko <alexm src gnome org>]

commit ef31865b32cb3cdab2621701473af3b2a54ac1e9
Author: Alexander Mikhaylenko <alexm gnome org>
Date:   Tue Dec 29 05:17:05 2020 +0500

    display-view: Remove extra widget on reset
    
    Fixes a part of https://gitlab.gnome.org/GNOME/gnome-games/-/issues/330

 src/ui/display-view.vala | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/ui/display-view.vala b/src/ui/display-view.vala
index aac71c32..c4df45da 100644
--- a/src/ui/display-view.vala
+++ b/src/ui/display-view.vala
@@ -623,6 +623,7 @@ private class Games.DisplayView : Gtk.Box, UiView {
                runner = null;
                media_button.media_set = null;
                secondary_menu_button.visible = false;
+               extra_widget = null;
 
                update_actions ();
        }