Run auto config test several times, sometimes OBS will crash.

Operating System Info

Windows 10

Other OS

No response

OBS Studio Version

Other

OBS Studio Version (Other)

30.1.2

OBS Studio Log URL

https://obsproject.com/logs/sbdvXu44lSfULNBu

OBS Studio Crash Log URL

https://obsproject.com/logs/S5FEASeCcYNKTfLn

Expected Behavior

app will not crash.

Current Behavior

Run auto config test several times, sometimes app will crash.And the crash reasons are same, the reason is about audio_callback.
debug source code - exception unhandled

Steps to Reproduce

1.click tools
2.click Auto-Configuration Wizard
3.click Next until stream warning and click Yes
4.sometimes when the bandwitdh test, app will crash cause by audio_callback.

And I try to debug source code, I find out the root cause is ”read access violiaton“, mx was nullptr.

In my opinion, according to my debug analysis, other thread(ucrtbased.dll thread) destroy the obs->video.mixes_mutex, and in
audio_callback function, pthrea_mutex_unlock will get the mixes_mutex which is nullpter.And crash happened.

Anything else we should know?

No response

### Tasks

Start with the linked crash log and the audio_callback path while reproducing the Auto-Configuration Wizard bandwidth test on Windows 10. Trace the lifetime of obs->video.mixes_mutex and compare it with the reported null access. Done means repeated wizard runs no longer crash, with the relevant regression behavior verified.