Use Immutable Record for accounts in Redux state (#26559)

app/javascript/mastodon/features/list_editor/components/account.jsx

@@ -39,7 +39,7 @@ const mapDispatchToProps = (dispatch, { accountId }) => ({
 class Account extends ImmutablePureComponent {
 
   static propTypes = {
-    account: ImmutablePropTypes.map.isRequired,
+    account: ImmutablePropTypes.record.isRequired,
     intl: PropTypes.object.isRequired,
     onRemove: PropTypes.func.isRequired,
     onAdd: PropTypes.func.isRequired,