Fade-in from zero volume does not work with "SoundInstance.fade"

The SoundInstance.fade Scripting API does not correctly increase the volume when fading from 0.0 to a higher value. When a sound starts at zero volume and fade is called with a target volume greater than zero, the volume remains at 0.0 instead of gradually increasing.

Steps to reproduce:

• Download the attached testing add-on.

• Create or open a world with the Beta APIs enabled.

• Run /king:sounds to open the testing UI.

• Start the sound at 0.0 volume and fade it to a higher value (for example, 50.0).

Observed results:

• The sound remains silent.

• The volume never increases from 0.0, despite the fade operation being initiated.

Expected results:

• The sound should smoothly fade from 0.0 to the specified target volume over the configured duration.

See the attached video for a demonstration of the issue.