[glade] GladeSignalEditor: plug glade widget leak

[Juan Pablo Ugarte <jpu src gnome org>]

commit aec114b6c11a2943a48e41a34250f1e608044b2a
Author: Juan Pablo Ugarte <juanpablougarte gmail com>
Date:   Fri Aug 7 11:38:50 2020 -0300

    GladeSignalEditor: plug glade widget leak
    
    Unref widget property on finalize.

 gladeui/glade-signal-editor.c | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/gladeui/glade-signal-editor.c b/gladeui/glade-signal-editor.c
index e7b8f4284..060c100da 100644
--- a/gladeui/glade-signal-editor.c
+++ b/gladeui/glade-signal-editor.c
@@ -826,6 +826,7 @@ glade_signal_editor_dispose (GObject *object)
   GladeSignalEditor *editor = GLADE_SIGNAL_EDITOR (object);
   GladeSignalEditorPrivate *priv = glade_signal_editor_get_instance_private (editor);
 
+  g_clear_object (&priv->widget);
   g_clear_object (&priv->detail_store);
   g_clear_object (&priv->handler_store);