Feature Request - Join group call in listen-only mode (without mic)

**Is your feature request related to a problem? Please describe.**
We need to implement a group call in which most participants are just an audience. Right now, even if a user joins a call with audio muted, they're still asked for microphone permission. If permission is not requested, the join call takes about 20-25 additional seconds to succeed. This is bad user experience.

**Describe the solution you'd like**
User should be able to join a call seamlessly even without a microphone.

**Describe alternatives you've considered**
Couldn't find any API that will let me do this. I posted the problem on [microsoft Q&A](https://docs.microsoft.com/en-us/answers/questions/546007/acs-group-call-join-in-listen-only-mode.html). The reply there says it is not yet supported, and that I should post a request here.

**Note**
This is a feature-request and not a bug report, but I'm unable to edit the labels.