Bug 1849124 - Make sure card-container calls MozLitElement's disconnectedCallback. r=fxview-reviewers,kcochrane

Depends on D187506

Differential Revision: https://phabricator.services.mozilla.com/D187507

browser/components/firefoxview/card-container.mjs

@@ -56,8 +56,6 @@ class CardContainer extends MozLitElement {
     }
   }
 
-  disconnectedCallback() {}
-
   onToggleContainer() {
     this.isExpanded = this.detailsExpanded;
     if (this.preserveCollapseState) {