fix: disconnect popup destroy signal in disable() (EGO-L-003)

Store the popup's 'destroy' handler id and disconnect it in disable(),
  so every signal connected at runtime has a matching disconnect, per the
  GNOME extension review guidelines.

Author: MehmetNuri

extension.js

@@ -261,6 +261,7 @@ class AudioOutputSwitcherExtension {
         this._manager = null;
         this._keybindingAction = null;
         this._popup = null;
+        this._popupDestroyId = 0;
     }
 
     enable() {
@@ -278,6 +279,10 @@ class AudioOutputSwitcherExtension {
         this._removeKeybinding();
 
         if (this._popup) {
+            if (this._popupDestroyId) {
+                this._popup.disconnect(this._popupDestroyId);
+                this._popupDestroyId = 0;
+            }
             this._popup.destroy();
             this._popup = null;
         }
@@ -332,9 +337,11 @@ class AudioOutputSwitcherExtension {
 
         const popup = new OutputSwitcherPopup(outputs, this._keybindingAction, this._manager);
         this._popup = popup;
-        popup.connect('destroy', () => {
-            if (this._popup === popup)
+        this._popupDestroyId = popup.connect('destroy', () => {
+            if (this._popup === popup) {
                 this._popup = null;
+                this._popupDestroyId = 0;
+            }
         });
 
         const shown = popup.show(