Make the dropdown list items accessible
### Node Version

20.18.1

### NPM/Yarn/PNPM Version

10.8.2

### Strapi Version

5.6.0

### Operating System

MacOS

### Database

PostgreSQL

### Javascript or Typescript

Typescript

### Reproduction URL

_No response_

### Bug Description

As a user I want to know when a dropdown list is scrollable.

With the current implementation, when opening a list it's not intuitive that the element contains additional content which can be scrolled. This has caused confusion with users assuming their content is missing.

A scrollable bar was present in Strapi 4 which indicated to the user, that the element is scrollable.

### Steps to Reproduce

1. Open a dropdown list with multiple elements. For example 5 or more items
2. User doesn't know this element can be scrolled
3. User assumes theres something wrong with content items

### Expected Behavior

As a user I want to know when a dropdown list is scrollable.

### Logs

```shell

```

### Code Snippets

_No response_

### Media

https://github.com/user-attachments/assets/48ea839a-dc90-46c6-bf24-facac5575150

### Additional information

_No response_

### Confirmation Checklist

- [x] I have checked the existing [issues](https://github.com/strapi/strapi/issues) for duplicates.
- [x] I agree to follow this project's [Code of Conduct](https://github.com/strapi/strapi/blob/develop/CODE_OF_CONDUCT.md).