[gnome-shell] workspaceThumbnail: Destroy thumbnails on destruction

[Marge Bot <marge-bot src gnome org>]

commit e9119c625dc22d892bdf04be6e9d56d598feabbe
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Tue May 25 12:03:46 2021 -0300

    workspaceThumbnail: Destroy thumbnails on destruction
    
    Often, when using multiple monitors, the thumbnails box may be
    destroyed before the 'hidden' signal of the Overview is emitted,
    which leaves a bunch of lingering signal connections to the
    workspace manager.
    
    Call this._destroyThumbnails() in the _onDestroy handler, which
    disconnects from workspace manager. This fixes the some of the log
    spam that GNOME Shell produces with backtraces of destroyed actors.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1860>

 js/ui/workspaceThumbnail.js | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/js/ui/workspaceThumbnail.js b/js/ui/workspaceThumbnail.js
index 3a7d916ca2..412527c938 100644
--- a/js/ui/workspaceThumbnail.js
+++ b/js/ui/workspaceThumbnail.js
@@ -720,6 +720,7 @@ var ThumbnailsBox = GObject.registerClass({
     }
 
     _onDestroy() {
+        this._destroyThumbnails();
         this._unqueueUpdateStates();
 
         if (this._scrollValueId)