Properly dispose monako tab models

packages/repl/src/components/editor/Editor.tsx

@@ -134,6 +134,7 @@ export default function Editor(props: EditorProps) {
       // a tab was deleted
       const changed = findChangedTab(tabs, prevTabs)
       if (!changed) return
+      modelsByTab.get(changed.id)?.dispose()
       modelsByTab.delete(changed.id)
     }
   }))