Drag handles don't read the aria-describedby on FireFox

## Context

Users with screen reader enabled, attempting to reorder sortable items with handles.

## Stack

- Mac Sequoia 15.3.2
- FireFox 136.0.2
- VoiceOver

## Issue

`aria-describedby` doesn't get read when focus is on a drag handle. Instead, the usual "image draggable group ${current} of ${total} " reads out.

## Impact

SR users on FireFox have no way to know how to pick up or drop the item.

## Steps to reproduce

1. Open VoiceOver on Mac
2. Open FireFox
3. Navigate to a dndkit example with drag handles, such as [this one](https://experimental--5fc05e08a4a65d0021ae0bf2.chromatic.com/?path=/story/react-sortable-tree--example).
4. Arrow or tab to the drag handle of an item.
- Expect to hear "image draggable group ${current} of ${total} "
- Expect _not_ to hear the instructions on how to pick up an item with spacebar, etc.

## Notes

Let me know if it would be helpful for me to make a video with a repro, happy to do so!