Fix EW crashing on incoming call (audio is undefined)

[toger5]

EW was crashing whenever there was an incoming call.

Checklist

• Tests written for new code (and old code if feasible).
• New or updated public/exported symbols have accurate TSDoc documentation.
• Linter and other CI checks pass.
• Sign-off given on the changes (see CONTRIBUTING.md).

[t3chguy]

Ah balls, looks like the move to AudioContext API missed a bit, this is not the right solution however. I will take it on as maintainer

[toger5]

Oh thanks @t3chguy.
I was not sure if I overlooked this at some point in time.

Thanks for doing this properly.