Audio pointer may be null during shutdown

### Operating System Info

Windows 11

### Other OS

_No response_

### OBS Studio Version

32.0.2

### OBS Studio Version (Other)

_No response_

### OBS Studio Log URL

-

### OBS Studio Crash Log URL

_No response_

### Expected Behavior

-

### Current Behavior

-

### Steps to Reproduce

-

### Anything else we should know?

Reopen as ticket from #12885 