Audio RED support

[fgutmann]

Is your feature request related to a problem? Please describe.

Android supports enabling Audio RED (redundant encoding) using the AudioTrackPublishOptions.

Javascript supports the same flag using the TrackPublishOptions

It seems RED is currently not supported in the swift SDK at all.

Describe the solution you'd like

Add the red boolean property to AudioPublishOptions, like it exists on Android and Javascript SDKs.

Describe alternatives you've considered

none

Additional context

N/A

[pblazej]

@fgutmann the option is indeed missing, however it should be enabled by default on the RTC side (Android disables that based on the flag).