[Bug Report] Screen reader is not announcing name and position of list items.

### Element UI version
2.15.14

### OS/Browsers version
OS: Windows 11 Version 24H2 (OS Build 26120.1542) Browser: Microsoft New Edge (Version 128.0.2739.42) (Official build) (64-bit)

### Vue version
2.7.16

### Reproduction Link
https://codepen.io/PoovizhiV/pen/yLmyZzw

### Steps to reproduce
Open the URL: https://codepen.io/PoovizhiV/pen/yLmyZzw in New Edge /Chrome browsers.
'ElementUI' page gets displayed.
Navigate to any dropdown using tab key and expand it using Enter key.
Verify whether the Screen reader is announcing name and position of list item in detail or not.

### What is Expected?
Here, after expanding the combo box, screen reader focus should move on the list teams and also it should read name and position of list items as option 1 of 4.

### What is actually happening?
Screen reader is not narrating name and position of list items when navigated using arrow keys because here focus is not going on list items present under the dropdown. Screen reader announces as blank.

https://github.com/user-attachments/assets/db702d55-8224-4ce2-91a3-307837b06534

Start with the linked CodePen reproduction and inspect the dropdown behavior when expanded and navigated with arrow keys. Confirm whether focus reaches each list item and whether its name and position are announced; the issue is done when the expected option information is conveyed by the screen reader.

Written by the indexing model from the issue text.