The "No device" option isn't displayed in the "Input/Output" drop-down boxes

Environment

Second Life Release 7.1.9.9620320242 (64bit)
Release Notes

You are at 9.4, 238.5, 21.5 in Product Engine 2 located at simhost-0e311690c9759c6aa.agni
SLURL: http://maps.secondlife.com/secondlife/Product%20Engine%202/9/239/22
(global coordinates 336,905.0, 307,438.0, 21.5)
Second Life Server 2024-06-11.9458617693
Release Notes

CPU: AMD Ryzen 5 3600 6-Core Processor (3600.01 MHz)
Memory: 16334 MB
OS Version: Microsoft Windows 10 64-bit (Build 19045.4598)
Graphics Card Vendor: NVIDIA Corporation
Graphics Card: NVIDIA GeForce RTX 2060/PCIe/SSE2

Windows Graphics Driver Version: 32.0.15.5612
OpenGL Version: 4.6.0 NVIDIA 556.12

Window size: 1920x1017
Font Size Adjustment: 96pt
UI Scaling: 1
Draw distance: 128m
Bandwidth: 3000kbit/s
LOD factor: 1.5
Render quality: 4
Texture memory: 5186MB
Disk cache: Max size 1638.4 MB (0.4% used)

J2C Decoder Version: KDU v7.10.4
Audio Driver Version: OpenAL, version 1.1 ALSOFT 1.23.1 / OpenAL Community / OpenAL Soft: OpenAL Soft
Dullahan: 1.14.0.202310131404
CEF: 118.4.1+g3dd6078+chromium-118.0.5993.54
Chromium: 118.0.5993.54
LibVLC Version: 3.0.16
Voice Server Version: Vivox 4.10.0000.32327.5fc3fe7c.5942f08

Packets Lost: 16/8,439 (0.2%)

Description

See the "Reproduction steps".

Reproduction steps

1. Login to the viewer.
2. Open the "Preferences" floater.
3. Select the "Sound & Media" tab.
4. Click on the "Voice Input/Output devices" button.
5. Click on the Input drop-down box.

Actual result: The "No device" option isn't displayed in the "Input/Output" drop-down boxes.
Expected result: The "No device" option should be displayed in the "Input/Output" drop-down boxes.

Note:
The "No device" option should be present in the "Input/Output drop-down" boxes according to the Viewer Preferences Test Plan in the "Output device" test case: https://lindenlab.atlassian.net/wiki/spaces/QA/pages/2698117145/Viewer+Preferences+Test+Plan#5.7.3-Output-device
This issue isn't reproduced in the production build.
This issue is reproduced on Win10/OSX.

Reproduce the issue through Preferences > Sound & Media > Voice Input/Output devices, checking both drop-down boxes and comparing with the production build. Consult the linked Viewer Preferences Test Plan output-device case; done means the “No device” option appears in the Input and Output lists on Windows and macOS.