fix(accordion): apply carbon element decorator for accordion skeleton (#11989)

### Related Ticket(s)

Closes # {{Provide issue number link(s) to the related ticket(s) that this pull request addresses}}

### Description

Adopter running into issues with accordion component when using the accordion in multiple libraries as the `accordion-skeleton` component is not using the `carbonElement` decorator.

This PR also fixes a couple smaller issues with missing the `select` import in the `pagination/index.js` file and missing stylesheet import for the `dropdown` stackblitz example

### Changelog

**Changed**

- `accordion-skeleton` to use custom `carbonElement` decorator
- add `select` import in the `pagination/index.js` file
- include stylesheet import in the `dropdown` example

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Author: annawen1

packages/carbon-web-components/examples/codesandbox/basic/components/dropdown/cdn.html

@@ -14,7 +14,7 @@
   <link rel="stylesheet"
         href="https://1.www.s81c.com/common/carbon-for-ibm-dotcom/tag/v1/latest/plex.css"/>
   <link rel="stylesheet" href="https://1.www.s81c.com/common/carbon/web-components/tag/v2/latest/grid.css" />
-  <link rel="stylesheet" href="https://1.www.s81c.com/common/carbon/web-components/tag/v2/latest/themes.css" /> 
+  <link rel="stylesheet" href="https://1.www.s81c.com/common/carbon/web-components/tag/v2/latest/themes.css" />
   <style>
     /* Suppress custom element until styles are loaded */
     cds-dropdown:not(:defined) {

packages/carbon-web-components/examples/codesandbox/basic/components/dropdown/index.html

@@ -13,6 +13,8 @@
   <meta charset="UTF-8" />
   <link rel="stylesheet"
         href="https://1.www.s81c.com/common/carbon-for-ibm-dotcom/tag/v1/latest/plex.css"/>
+
+  <link rel="stylesheet" href="src/styles.scss" />
   <style>
     /* Suppress custom element until styles are loaded */
     cds-dropdown:not(:defined) {

packages/carbon-web-components/src/components/accordion/accordion-skeleton.ts

@@ -1,15 +1,15 @@
 /**
  * @license
  *
- * Copyright IBM Corp. 2019, 2023
+ * Copyright IBM Corp. 2019, 2024
  *
  * This source code is licensed under the Apache-2.0 license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
 import { classMap } from 'lit/directives/class-map.js';
 import { LitElement, html } from 'lit';
-import { property, customElement } from 'lit/decorators.js';
+import { property } from 'lit/decorators.js';
 import { prefix } from '../../globals/settings';
 import { ACCORDION_ALIGNMENT } from './accordion';
 import { forEach } from '../../globals/internal/collection-helpers';
@@ -18,6 +18,8 @@ import './accordion-item-skeleton';
 import '../skeleton-text/index';
 import styles from './accordion.scss';
 
+import { carbonElement as customElement } from '../../globals/decorators/carbon-element';
+
 /**
  * Skeleton of code snippet.
  */

packages/carbon-web-components/src/components/pagination/index.ts

@@ -1,11 +1,12 @@
 /**
  * @license
  *
- * Copyright IBM Corp. 2021, 2023
+ * Copyright IBM Corp. 2021, 2024
  *
  * This source code is licensed under the Apache-2.0 license found in the
  * LICENSE file in the root directory of this source tree.
  */
 
 import '../select/select-item';
+import '../select/select';
 import './pagination';