fix(upgrade): correctly destroy nested downgraded component (#22400)

Previously, when a downgraded component was destroyed in a way that did
not trigger the `$destroy` event on the element (e.g. when a parent
element was removed from the DOM by Angular, not AngularJS), the
`ComponentRef` was not destroyed and unregistered.
This commit fixes it by listening for the `$destroy` event on both the
element and the scope.

Fixes #22392

PR Close #22400

packages/upgrade/src/dynamic/upgrade_ng1_adapter.ts

@@ -263,6 +263,8 @@ class UpgradeNg1ComponentAdapter implements OnInit, OnChanges, DoCheck {
     if (this.controllerInstance && isFunction(this.controllerInstance.$onDestroy)) {
       this.controllerInstance.$onDestroy();
     }
+
+    this.componentScope.$destroy();
   }
 
   setComponentProperty(name: string, value: any) {