[Software Issue] Intermittent crashes while attempting to display audio device error popups

[tmiw]

Platform

Windows

Platform Version

11

FreeDV Version

2.0.0 - eded776

Steps to Reproduce

1. Deny access to microphone on PC.
2. Push Start button in FreeDV

Expected Behavior

Popup message explaining that it can't access the audio device. FreeDV should stop to allow user to fix audio configuration.

As a bonus, it would be good to detect the "microphone deny" scenario before starting and provide feedback to the user as to how to resolve.

Actual Behavior

FreeDV intermittently crashes on startup while attempting to display the popup.

Additional Comments

Discovered while developing Windows CI tests for #761.