Speaker selection HTML element not visible on Firefox (Extension configuration -> Audio & Video -> Speaker)

Tested on Firefox versions:
- 146.0a1 (2025-11-07) (64-bit)
- 145.0.1 (64-bit)
<img width="897" height="403" alt="Image" src="https://github.com/user-attachments/assets/32b7832b-3dfc-43d6-a407-0ceb0bce6c11" />


<img width="540" height="163" alt="Image" src="https://github.com/user-attachments/assets/af6452b5-ca64-44e7-b20b-ff95485689e8" />

