Bug 1650795 - Update PopupNotifications to check suppressed state on tab switch. r=Gijs

Differential Revision: https://phabricator.services.mozilla.com/D83630

toolkit/modules/PopupNotifications.jsm

@@ -777,11 +777,11 @@ PopupNotifications.prototype = {
         }
       // fall through
       case "TabSelect":
-        let self = this;
         // setTimeout(..., 0) needed, otherwise openPopup from "activate" event
         // handler results in the popup being hidden again for some reason...
-        this.window.setTimeout(function() {
-          self._update();
+        this.window.setTimeout(() => {
+          this._suppress = this._shouldSuppress();
+          this._update();
         }, 0);
         break;
       case "click":